Journal articles on the topic 'Groundwater flow Measurement Mathematical models'
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Krusteva, Ekaterina D., Stefan Y. Radoslavov, and Zdravko I. Diankov. "Modelling the Seepage of Groundwater: Application of the Viscous Analogy and Numerical Methods." Applied Rheology 9, no. 4 (August 1, 1999): 165–71. http://dx.doi.org/10.1515/arh-2009-0012.
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Abstract The application of the viscous analogy, known as the Hele-Show model, for seepage investigation is demonstrated in the paper. The changes in the viscous properties of the model fluid (glycerine) resulting from the changes of the atmospheric conditions - temperature and humidity, have been taken under consideration as factors influencing the flow discharge in the model. A method has been substantiated for the exact quantitative comparison of discharges obtained under different boundary conditions of the seepage process using parallel rheological measurements of the model fluid. The results from the viscous and mathematical models are compared for a particular two-dimensional seepage process - the operation of a horizontal drainage. The complete coincidence of these results, proves the good grounds of the method as well as its applicability as a test method for the development of mathematical models.
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Yang, Bin, Tianhong Yang, Zenghe Xu, Honglei Liu, Wenhao Shi, and Xin Yang. "Numerical simulation of the free surface and water inflow of a slope, considering the nonlinear flow properties of gravel layers: a case study." Royal Society Open Science 5, no. 2 (February 2018): 172109. http://dx.doi.org/10.1098/rsos.172109.
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Groundwater is an important factor of slope stability, and 90% of slope failures are related to the influence of groundwater. In the past, free surface calculations and the prediction of water inflow were based on Darcy's law. However, Darcy's law for steady fluid flow is a special case of non-Darcy flow, and many types of non-Darcy flows occur in practical engineering applications. In this paper, based on the experimental results of laboratory water seepage tests, the seepage state of each soil layer in the open-pit slope of the Yanshan Iron Mine, China, were determined, and the seepage parameters were obtained. The seepage behaviour in the silt layer, fine sand layer, silty clay layer and gravelly clay layer followed the traditional Darcy law, while the gravel layers showed clear nonlinear characteristics. The permeability increases exponentially and the non-Darcy coefficient decreases exponentially with an increase in porosity, and the relation among the permeability, the porosity and the non-Darcy coefficient is investigated. A coupled mathematical model is established for two flow fields, on the basis of Darcy flow in the low-permeability layers and Forchheimer flow in the high-permeability layers. In addition, the effect of the seepage in the slope on the transition from Darcy flow to Forchheimer flow was considered. Then, a numerical simulation was conducted by using finite-element software (FELAC 2.2). The results indicate that the free surface calculated by the Darcy–Forchheimer model is in good agreement with the in situ measurements; however, there is an evident deviation of the simulation results from the measured data when the Darcy model is used. Through a parameter sensitivity analysis of the gravel layers, it can be found that the height of the overflow point and the water inflow calculated by the Darcy–Forchheimer model are consistently less than those of the Darcy model, and the discrepancy between these two models increases as the permeability increases. The necessity of adopting the Darcy–Forchheimer model was explained. The Darcy–Forchheimer model would be applicable in slope engineering applications with highly permeable rock.
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Pourpak, Hamid, Bernard J. Bourbiaux, Frédéric Roggero, and Frederick Delay. "An Integrated Methodology for Calibrating a Heterogeneous/Fractured Reservoir Model From Wellbore Flow Measurements: Case Study." SPE Reservoir Evaluation & Engineering 12, no. 03 (May 31, 2009): 433–45. http://dx.doi.org/10.2118/113528-pa.
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Summary Reliable flow modeling of highly heterogeneous/fractured reservoirs necessarily goes through the calibration of poorly determined geological and/or petrophysical parameters to field flow measurements. To that end, optimization procedures based on gradient methods or on gradual-deformation techniques have been developed in recent years. This paper proposes a sequential method combining those two approaches. The case under consideration is a water-bearing reservoir constituted of heterogeneous, karstic and fractured limestones located near Poitiers, France. In a preliminary step, drilling, core, and log data acquired in approximately 30 wells were integrated into a geostatistical facies model used as the support for flow simulation. First the facies petrophysical properties of this model were calibrated to well pumping and interference responses within a gradient-based inversion loop. Flow responses could be reproduced, with the exception of a few "problematic" observation wells. Second the gradual-deformation method was applied, globally then locally, to improve the distribution of facies while keeping the previously optimized petrophysical properties. The problematic wells' responses could be reproduced better without altering the other wells' match. Furthermore, that good match of calibration wells was obtained on a simplified geostatistical model involving fewer facies than in the initial model. The gradual-deformation method then appears as a robust and effective approach to find a model best matching a set of flow data among equiprobable geostatistical models. To conclude, the sequential-modeling method demonstrated herein is an effective way to actually integrate geological and flow data and to link geosciences and reservoir-engineering skills, for setting up consistent models of hardly tractable highly heterogeneous reservoirs. Introduction During the past 20 years, the technique of mathematical modeling has been used extensively in the study of groundwater-resources management and aquifer remediation (Sun 1994). Concern was especially focused on fluid transfer in heterogeneous and/or fractured reservoirs. That resulted in conclusive advances in the characterization and modeling of fractured reservoirs (Cacas et al. 2001). Actually, wellbore information on underground reservoir heterogeneities and fractures (e.g., core descriptions, image logs, and production profiles) is now used to condition the geostatistical pixel-based models or the object-based stochastic models of these reservoirs and to calibrate the hydraulic properties of major flow heterogeneities such as fractures (Sarda et al. 2002). However, the problem of reservoir-model construction remains highly undetermined. The purpose of this paper is to design and validate an inversion method for calibrating the poorly defined flow models of highly heterogeneous reservoirs to wellbore dynamic data. The design and the application of that method are performed on an experimental hydrogeological site (EHS) settled on a karstic and fractured limestone aquifer located near Poitiers, France. The flow model is based on a geostatistical distribution of facies. The method involves two successive steps:the inversion of facies petrophysical properties andthe gradual deformation of the facies distribution. The resulting model is shown to predict well responses effectively. Finally, the possibility of further calibration improvement is investigated by means of alternative flow-modeling approaches, such as the use of a dual-porosity model or a more accurate modeling of conductive bodies.
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Mahmood, Mohammed Shuker, and D. Lesnic. "Identification of conductivity in inhomogeneous orthotropic media." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 1 (January 7, 2019): 165–83. http://dx.doi.org/10.1108/hff-11-2017-0469.
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Purpose The purpose of this paper is to solve numerically the identification of the thermal conductivity of an inhomogeneous and possibly anisotropic medium from interior/internal temperature measurements. Design/methodology/approach The formulated coefficient identification problem is inverse and ill-posed, and therefore, to obtain a stable solution, a non-linear regularized least-squares approach is used. For the numerical discretization of the orthotropic heat equation, the finite-difference method is applied, while the non-linear minimization is performed using the MATLAB toolbox routine lsqnonlin. Findings Numerical results show the accuracy and stability of solution even in the presence of noise (modelling inexact measurements) in the input temperature data. Research limitations/implications The mathematical formulation uses temporal temperature measurements taken at many points inside the sample, and this may be too much information that is provided to identify a space-wise dependent only conductivity tensor. Practical implications As noisy data are inverted, the paper models real situations in which practical temperature measurements recorded using thermocouples are inherently contaminated with random noise. Social implications The identification of the conductivity of inhomogeneous and orthotropic media will be of great interest to the inverse problems community with applications in geophysics, groundwater flow and heat transfer. Originality/value The current investigation advances the field of coefficient identification problems by generalizing the conductivity to be anisotropic in addition of being heterogeneous. The originality lies in performing, for the first time, numerical simulations of inversion to find the orthotropic and inhomogeneous thermal conductivity from noisy temperature measurements. Further value and physical significance are brought in by determining the degree of cure in a resin transfer molding process, in addition to obtaining the inhomogeneous thermal conductivity of the tested material.
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Fowler, A. C., and C. G. Noon. "Mathematical models of compaction, consolidation and regional groundwater flow." Geophysical Journal International 136, no. 1 (January 1, 1999): 251–60. http://dx.doi.org/10.1046/j.1365-246x.1999.00717.x.
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Emikh, V. N. "Mathematical models of groundwater flow with a horizontal drain." Water Resources 35, no. 2 (March 2008): 205–11. http://dx.doi.org/10.1134/s0097807808020097.
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Lo, Weicheng, Sanidhya Nika Purnomo, Bondan Galih Dewanto, Dwi Sarah, and Sumiyanto. "Integration of Numerical Models and InSAR Techniques to Assess Land Subsidence Due to Excessive Groundwater Abstraction in the Coastal and Lowland Regions of Semarang City." Water 14, no. 2 (January 11, 2022): 201. http://dx.doi.org/10.3390/w14020201.
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This study was carried out to assess land subsidence due to excessive groundwater abstraction in the northern region of Semarang City by integrating the application of both numerical models and geodetic measurements, particularly those based on the synthetic aperture radar interferometry (InSAR) technique. Since 1695, alluvial deposits caused by sedimentations have accumulated in the northern part of Semarang City, in turn resulting in changes in the coastline and land use up to the present. Commencing in 1900, excessive groundwater withdrawal from deep wells in the northern section of Semarang City has exacerbated natural compaction and aggravated the problem of land subsidence. In the current study, a groundwater model equivalent to the hydrogeological system in this area was developed using MODFLOW to simulate the hydromechanical coupling of groundwater flow and land subsidence. The numerical computation was performed starting with the steady-state flow model from the period of 1970 to 1990, followed by the model of transient flow and land subsidence from the period of 1990 to 2010. Our models were calibrated with deformation data from field measurements collected from various sources (e.g., leveling, GPS, and InSAR) for simulation of land subsidence, as well as with the hydraulic heads from observation wells for simulation of groundwater flow. Comparison of the results of our numerical calculations with recorded observations led to low RMSEs, yet high R2 values, mathematically indicating that the simulation outcomes are in good agreement with monitoring data. The findings in the present study also revealed that land subsidence arising from groundwater pumping poses a serious threat to the northern part of Semarang City. Two groundwater management measures are proposed and the future development of land subsidence is accordingly projected until 2050. Our study shows quantitatively that the greatest land subsidence occurs in Genuk District, with a magnitude of 36.8 mm/year. However, if the suggested groundwater management can be implemented, the rate and affected area of land subsidence can be reduced by up to 59% and 76%, respectively.
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Boyraz, Uğur, and Cevza Melek Kazezyılmaz-Alhan. "Solutions for groundwater flow with sloping stream boundary: analytical, numerical and experimental models." Hydrology Research 49, no. 4 (June 9, 2017): 1120–30. http://dx.doi.org/10.2166/nh.2017.264.
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Abstract Protecting groundwater resources plays an important role in watershed management. For this purpose, studies on groundwater flow dynamics incorporating surface water–groundwater interactions have been conducted including analytical, numerical, and experimental models. In this research, a stream–aquifer system was considered to understand the physical behavior of surface water–groundwater interactions. Interactions in a stream–aquifer system were incorporated into the mathematical modeling by defining the stream head as a boundary condition for the groundwater flow equation. This boundary was chosen as a sloping stream boundary, which is an approach in representing the natural conditions of the stream and may be used to define continuous interactions between stream and aquifer. A semi-analytical solution for transient 2D groundwater flow was developed for the considered problem. Isotropic, homogeneous, and finite aquifer assumptions were made in order to define the aquifer characteristics. Then, a series of laboratory experiments was conducted to simulate this stream–aquifer system. Finally, a numerical model was developed by using Visual MODFLOW to verify analytical and experimental results. Numerical results matched with both analytical solutions and the experimental observations.
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Yakirevich, Alexander. "Water Flow, Solute and Heat Transfer in Groundwater." Water 12, no. 7 (June 28, 2020): 1851. http://dx.doi.org/10.3390/w12071851.
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Groundwater is an essential and vital water resource for drinking water production, agricultural irrigation, and industrial processes. The better understanding of physical and chemical processes in aquifers enables more reliable decisions and reduces the investments concerning water management. This Special Issue on “Water Flow, Solute and Heat Transfer in Groundwater” of Water focuses on the recent advances in groundwater dynamics. In this editorial, we introduce 12 high-quality papers that cover a wide range of issues on different aspects related to groundwater: protection from contamination, recharge, heat transfer, hydraulic parameters estimation, well hydraulics, microbial community, colloid transport, and mathematical models. By presenting this integrative volume, we aim to transfer knowledge to hydrologists, hydraulic engineers, and water resources planners who are engaged in the sustainable development of groundwater resources.
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Flowers, Gwenn E. "Modelling water flow under glaciers and ice sheets." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2176 (April 2015): 20140907. http://dx.doi.org/10.1098/rspa.2014.0907.
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Recent observations of dynamic water systems beneath the Greenland and Antarctic ice sheets have sparked renewed interest in modelling subglacial drainage. The foundations of today's models were laid decades ago, inspired by measurements from mountain glaciers, discovery of the modern ice streams and the study of landscapes evacuated by former ice sheets. Models have progressed from strict adherence to the principles of groundwater flow, to the incorporation of flow ‘elements’ specific to the subglacial environment, to sophisticated two-dimensional representations of interacting distributed and channelized drainage. Although presently in a state of rapid development, subglacial drainage models, when coupled to models of ice flow, are now able to reproduce many of the canonical phenomena that characterize this coupled system. Model calibration remains generally out of reach, whereas widespread application of these models to large problems and real geometries awaits the next level of development.
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Vinda, Ram Raj, Raja Ram Yadava, and Naveen Kumar. "Uniform Horizontal Groundwater Flow against Dispersion in a Shallow Aquifer: Two Analytical Models." Hydrology Research 23, no. 1 (February 1, 1992): 1–12. http://dx.doi.org/10.2166/nh.1992.0001.
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Analytical solutions converging rapidly at large and small values of times have been obtained for two mathematical models which describe the concentration distribution of a non reactive pollutant from a point source against the flow in a horizontal cross-section of a finite saturated shallow aquifer possessing uniform horizontal groundwater flow. Zero concentration or the conditions in which the flux across the extreme boundaries are proportional to the respective flow components are applied. The effects of flow and dispersion on concentration distribution are also discussed.
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Smith, W. R., G. C. Wake, J. E. McIntosh, R. P. McIntosh, M. Pettigrew, and R. Kao. "Mathematical analysis of perifusion data: models predicting elution concentration." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 261, no. 1 (July 1, 1991): R247—R256. http://dx.doi.org/10.1152/ajpregu.1991.261.1.r247.
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System models are constructed and analyzed for combined convective flow and for dispersion in distorting concentrations of a chemical signal as it passes through a packed column. We derive general analytical solutions for these models. The results have applications to analyses such as in biological experiments involving hormonal stimulation of perifused cells, elution chromatography, adsorption columns, and studies of groundwater flow. The models reveal that the column distorts an incoming signal (such as a change in solute concentration in the flowing liquid) at the inlet. This distortion is greatest at low values of the Peclet number of the flow and is small at larger values. We explore the effects of the approximations inherent in the mathematical models of the system. Specification of the boundary conditions of the problem are shown to be particularly important. With the use of incorrect models, it is possible to obtain accurate interpolations to data obtained from perfusion experiments. However, the parameters derived (in particular the dispersion constant and the peak concentration of a solute concentration pulse) may be considerably in error. This may lead to errors when these parameter estimates are used to predict results in other experimental situations.
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Gu, Lei Lei, Jing Li Shao, Yue Sun, and Yun Zhang Zhao. "Groundwater Flow Simulation and Resource Evaluation of the Affected Zone along the Yellow River (Henan Section)." Advanced Materials Research 610-613 (December 2012): 2713–18. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.2713.
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The purpose of this paper is to build a three-dimensional groundwater flow model of the affected zone along the Yellow River, and to conduct equilibrium analysis and resource evaluation to the groundwater of the research area according to the simulation results. In the beginning, the groundwater flow numerical simulation model (1999.1-2009.12) is established and verified through the GMS software on the basis of the establishment of hydrogeological conceptual and mathematical models. Results of the simulation model show that the perennial average of the resources of shallow groundwater recharge is 29.32×108m3/a, the average recharge modulus is 22.35×104m3/km2•a and the safe yield of groundwater resource is 27.04×108m3/a.
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Aniszewski, A. "Incorporation of advection and adsorption in modeling ground water quality." Water Supply 1, no. 2 (March 1, 2001): 231–35. http://dx.doi.org/10.2166/ws.2001.0042.
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A one-dimensional model of groundwater flow, incorporating advection and adsorption of conservative pollutants has been presented. Based on earlier laboratory experiments on physical models and adopting the numerical solution of the presented mathematical model, the adsorption parameters k1 and n have been calculated for a non-linear function describing this process. Empirical relationships for the adsorption parameters characteristic of the aquifer and the ground water flow have been developed. These relationships should allow for better forecasting and estimation of groundwater quality at the intake.
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Johnston, D. N., and J. E. Drew. "Measurement of Positive Displacement Pump Flow Ripple and Impedance." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 210, no. 1 (February 1996): 65–74. http://dx.doi.org/10.1243/pime_proc_1996_210_437_02.
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The secondary source method forms the British Standard for pump fluid-borne noise testing. This is a powerful technique but requires care in order to produce accurate results. This paper describes practical aspects for implementing the method. The requirements for the test rig, data acquisition system and analysis are detailed. The British Standard specifies that either mathematical modelling or linear interpolation is used on the source impedance measurements. A method for smoothing the impedance results is described in this paper, which is shown to give more repeatable results than linear interpolation. Some physically realistic mathematical models of pump impedance are described, and their use in determining the internal flow ripple discussed.
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Akanbi, Olanrewaju Akinfemiwa, and Moshood ‘Niyi Tijani. "Sustainability and Conceptual Groundwater Hydraulic Models of Basement Aquifers." Materials and Geoenvironment 66, no. 2 (June 1, 2019): 87–98. http://dx.doi.org/10.2478/rmzmag-2019-0016.
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AbstractGroundwater flow of the basement terrains of the Ibarapa region was studied by carrying out pumping test and measurement of borehole inventory. The view was to identify the associated aquifer systems from the time-drawdown curves, quantify the estimable hydraulic properties and develop hypothetical models for the understanding of the groundwater flow in the area underlain by diverse crystalline bedrocks. Three aquifer types were identified namely, dual, leaky and regolith. The yield of groundwater in dual and leaky aquifers that dominated terrains underlain by amphibolite and gneisses was sustainable, but the discharge of regolith aquifers mainly associated with migmatite and granite terrains declined at late pumping stage. The transmissivities of the dual and leaky aquifers were between 2.02 and 11.65 m2/day, while those of regolith aquifers were mostly less than 1.00 m2/day. The average aquifer transmissivities in m2/day by bedrocks were: 6.85, 2.57, 0.76 and 1.72, correspondingly. The inter-relationships between transmissivities and groundwater discharge showed diverse aquifer representations, from sustainable high-yielding to unsustainable low-yielding types. Conscientious effort is, therefore, required for well construction in the area.
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Παναγόπουλος, A., E. Δρακοπούλου, and V. Περλέρος. "APPLICATION OF THE MATHEMATICAL MODEL MODFLOW ON A KARSTIC AQUIFER: THE CASE OF VIOTIKOS KIFISOS BASIN." Bulletin of the Geological Society of Greece 36, no. 4 (January 1, 2004): 2021. http://dx.doi.org/10.12681/bgsg.16701.
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MODFLOW is a very well verified code of mathematical modeling for simulation of saturated groundwater flow in porous medium. Groundwater flow simulation in discontinuity media (i.e. media characterized by dominance of secondary and tertiary porosity as opposed to primary porosity), such as karstic aquifers, utilizing specialized models is problematic. Due to existing impedes the use of the conventional model MODFLOW was attempted for the simulation of the karstic system of the Viotikos Kifisos river aiming predominantly at assessing the potential, restrictions, particularities and conditions under which such a modelling code could be implemented, especially when relatively restricted volume of raw data is available. Compilation and calibration of the model suggest that MODFLOW may in general be implemented and can provide useful results. As in every mathematical model, knowledge of the assumptions made and the intrinsic restrictions involved is required, along with in-depth evaluation of its capabilities. The mathematical model of Viotikos Kifisos basin forms a valuable tool for management of its water resources and study of regional groundwater evolution.
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de Rooij, G. H. "Is the groundwater reservoir linear? A mathematical analysis of two limiting cases." Hydrology and Earth System Sciences Discussions 11, no. 1 (January 6, 2014): 83–108. http://dx.doi.org/10.5194/hessd-11-83-2014.
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Abstract. Storage–discharge relationships of the groundwater reservoirs of several catchments in a temperate-humid climate were reported in the literature to be seemingly non-linear. Once recharge was adequately accounted for during model calibration they turned out to be linear. The question was posed if this linearity was a fundamental property of groundwater reservoirs in general. A mathematical analysis based on analytical solutions for several cases involving parallel flow in horizontal aquifers shows that this is not the case when the surface water level is close to the aquifer bottom. When the aquifer is of constant thickness, linear-reservoir behaviour arises when the forcings remain constant for a sufficiently long time. This can range from a few weeks for aquifers with a dense drainage network of streams or ditches to years or centuries for large aquifers drained by rivers many kilometers apart. The characteristic time of the groundwater reservoir depends on whether or not the aquifer is leaky and recharge is non-zero. It is concluded that groundwater reservoirs can only be linear if their thickness can be assumed independent of the hydraulic head, and if they have a dense drainage network. Even then, they behave non-linearly up to several weeks after a change in recharge. Models that conceptualize the catchment as a configuration of coupled reservoirs will normally assign the groundwater discharge surplus generated because of the initially non-linear behaviour of the groundwater to their fast-responding reservoirs, thereby exaggerating the importance of fast-responding flow routes in a catchment.
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Koirala, Nischal, and Gordon McLennan. "Mathematical Models for Blood Flow Quantification in Dialysis Access Using Angiography: A Comparative Study." Diagnostics 11, no. 10 (September 26, 2021): 1771. http://dx.doi.org/10.3390/diagnostics11101771.
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Blood flow rate in dialysis (vascular) access is the key parameter to examine patency and to evaluate the outcomes of various endovascular interve7ntions. While angiography is extensively used for dialysis access–salvage procedures, to date, there is no image-based blood flow measurement application commercially available in the angiography suite. We aim to calculate the blood flow rate in the dialysis access based on cine-angiographic and fluoroscopic image sequences. In this study, we discuss image-based methods to quantify access blood flow in a flow phantom model. Digital subtraction angiography (DSA) and fluoroscopy were used to acquire images at various sampling rates (DSA—3 and 6 frames/s, fluoroscopy—4 and 10 pulses/s). Flow rates were computed based on two bolus tracking algorithms, peak-to-peak and cross-correlation, and modeled with three curve-fitting functions, gamma variate, lagged normal, and polynomial, to correct errors with transit time measurement. Dye propagation distance and the cross-sectional area were calculated by analyzing the contrast enhancement in the vessel. The calculated flow rates were correlated versus an in-line flow sensor measurement. The cross-correlation algorithm with gamma-variate curve fitting had the best accuracy and least variability in both imaging modes. The absolute percent error (mean ± SEM) of flow quantification in the DSA mode at 6 frames/s was 21.4 ± 1.9%, and in the fluoroscopic mode at 10 pulses/s was 37.4 ± 3.6%. The radiation dose varied linearly with the sampling rate in both imaging modes and was substantially low to invoke any tissue reactions or stochastic effects. The cross-correlation algorithm and gamma-variate curve fitting for DSA acquisition at 6 frames/s had the best correlation with the flow sensor measurements. These findings will be helpful to develop a software-based vascular access flow measurement tool for the angiography suite and to optimize the imaging protocol amenable for computational flow applications.
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Hajrah, Ardy Arsyad, and Achmad Zubair. "Modeling of Contaminant Transport and Groundwater Flow of Tamangapa Landfill in Makassar Indonesia." Applied Mechanics and Materials 567 (June 2014): 92–97. http://dx.doi.org/10.4028/www.scientific.net/amm.567.92.
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This paper aims to analyze the groundwater flow direction of Tamangapa landfill and to predict the contaminant in the groundwater over the period of 20 years, accounted for the year of 2000 until 2020. To understand the natural condition of the landfill, geological and hydrogeological survey were undertaken, consisting of geological survey, geomorphology and geo-resistivity surveys. Hydrogeological survey comprises groundwater level measurement, chemical analysis of leachate and groundwater samples which were later used as input data for numerical model. Based on the result of groundwater flow models, the direction of groundwater is found to be flowing from the north to the south. The minimum concentration for manganese (Mn) is 1.519 mg/l and 2.701 mg/l for iron (Fe). Over the period of 2020, Fe concentration increases significantly, reaching the level of 56.427 mg/l, Mn concentration for 299.5594 mg/l. It can be suggested that the groundwater quality of Tamangapa landfill has already exceeded the standard for water quality, leading to potential severe impact to local people around the landfill. Keywords: Landfill, modflow, groundwater, leachate, contaminant.
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Wali, Saadu Umar, Kabiru Jega Umar, and Isa Garba Abor. "Modelling Flow And Fate Of Contaminants In Groundwater Using A Version Of The Five Steady- State Pollutant Transport Models: A Status-Review." Journal of Electronics,Computer Networking and Applied Mathematics, no. 11 (August 19, 2021): 1–30. http://dx.doi.org/10.55529/jecnam.11.1.30.
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It is essential to understand pollutant flow and fate in the permeation zones for adequate groundwater quality protection. This review highlights the hydraulic controls on pollutant filtration into the groundwater. The study is divided into seven sections, viz: Numerical modelling of contaminants in aquifers; Modeling tool for pollutant flow, fate, and theorisation; Theoretical approaches to groundwater modelling; Model input variables; and Modeling the vertical flow of contaminants from surface water to aquifers; Recent advances; and Challenges of groundwater pollution modelling. The latter illustrates how contaminants flow are simulated in a saturated aquitard aquifer. Model Type 2 is applied to simulate contaminant flow in a fully splintered formation. Model Type 3 showed the vertical flow of contaminants within an unsaturated zone. The vertical flow of pollutants within an unsaturated region without a recharge is simulated using Model Type 4. Model Type 5 is applied to study gas-phase flow from a point situated within the un-inundated area beneath a confined zone, to the uppermost layer of the superimposed groundwater reservoir and then flow horizontally into the aquifer. Application of these models shows that an initial measurement with traditional, and repeatedly selecting none-site-specific factor. The models are qualitatively harmonious in conjunction with general trends in interpretations and offer a convenient approximation of pollution. However, the execution of these models is limited by a lack of adequate field data. Thus, the model output must be examined within the model uncertainty framework, data input limitations, and methodologically established standards from the literature.
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Tahershamsi, Ahmad, Atabak Feizi, and Siavash Molaei. "Modeling Groundwater Surface by MODFLOW Math Code and Geostatistical Method." Civil Engineering Journal 4, no. 4 (May 3, 2018): 812. http://dx.doi.org/10.28991/cej-0309135.
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Simulation of groundwater flow by mathematical model can be used for developing aquifer balance element analysis scenarios, explaining conditions of droughts, definition of prohibitive extraction policies and analyzing the qualitative models. In this study, the development of a quantitative model in terms of the main parameters affecting on the water surface changes has been performed for the Ardebil plain (located in NW of Iran). Accordingly, a comprehensive processing of raw data sets has been carried-out by means of MODFLOW mathematical model. Also to simulate the groundwater surface changes in the mentioned plain, the geo-statistical method has been used. Results indicate that the mathematical model used in the aquifer balance simulation for the Ardebil plain has approximately 2% relative normal root-mean-square error (NRMSE). This small NRSMSE confirms the model accuracy for the Ardebil plain using the calibration data. Moreover, comparing the results of this method and the ones obtained by mathematical model performed by examining some error criteria like RMSE, Mean, ASE and MS, it is found that the accuracy of the mathematical model is higher than the geostatistical method and the main reason for this is the distribution of uncertainty in a few available piezometric points in the geostatistical method.
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Mohammed, G. A., W. Zijl, O. Batelaan, and F. De Smedt. "Comparison of Two Mathematical Models for 3D Groundwater Flow: Block-Centered Heads and Edge-Based Stream Functions." Transport in Porous Media 79, no. 3 (February 4, 2009): 469–85. http://dx.doi.org/10.1007/s11242-009-9336-y.
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Xin, Yawen, Zhifang Zhou, Mingwei Li, and Chao Zhuang. "Analytical Solutions for Unsteady Groundwater Flow in an Unconfined Aquifer under Complex Boundary Conditions." Water 12, no. 1 (December 24, 2019): 75. http://dx.doi.org/10.3390/w12010075.
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The response laws of groundwater dynamics on the riverbank to river level variations are highly dependent on the river level fluctuation process. Analytical solutions are widely used to infer the groundwater flow behavior. In analytical calculations, the river level variation is usually generalized as instantaneous uplift or stepped, and then the analytical solution of the unsteady groundwater flow in the aquifer is derived. However, the river level generally presents a complex, non-linear, continuous change, which is different from the commonly used assumptions in groundwater theoretical calculations. In this article, we propose a piecewise-linear approximation to describe the river level fluctuation. Based on the conceptual model of the riverbank aquifer system, an analytical solution of unsteady groundwater flow in an unconfined aquifer under complex boundary conditions is derived. Taking the Xiluodu Hydropower Station as an example, firstly, the monitoring data of the river level during the period of non-impoundment in the study area are used to predict the groundwater dynamics with piecewise-linear and piecewise-constant step approximations, respectively, and the long-term observation data are used to verify the calculation accuracy for the different mathematical models mentioned above. During the reservoir impoundment period, the piecewise-linear approximation is applied to represent the reservoir water level variation, and to predict the groundwater dynamics of the reservoir bank.
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Μανάκος, A., and Γ. Δημόπουλος. "CONTRIBUTION OF SEASONAL STOCHASTIC MODELS SARIMA TO THE RATIONAL WATER RESOURCES MANAGEMENT. THE CASE OF THE KRANIA ELASSONA KARST SYSTEM, THESSALY, GREECE." Bulletin of the Geological Society of Greece 36, no. 4 (January 1, 2004): 2012. http://dx.doi.org/10.12681/bgsg.16700.
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Several stochastic models, known as Box and Jenkins or SARIMA (Seasonal Autoregressive Integrated Moving Average) have been used in the past for forecasting hydrological time series in general and stream flow or spring discharge time series in particular. SARIMA models became very popular because of their simple mathematical structure, convenient representation of data in terms of a relatively small number of parameters and their applicability to stationary as well as nonstationary process.Application of the seasonal stochastic model SARIMA to the spring's monthly discharge time series for the period 1974-1993 in Krania Elassona karst system yielded the following results. Logarithms of the monthly spring discharge time series can be simulated on a SARIMA (4,1,1)(1,1,1)12 type model. This type of model is suitable for the Krania Elassona karst system simulation and can be utilised as a tool to predict monthly discharge values at Kafalovriso spring for at least a 2 year period. Seasonal stochastic models SARIMA seem to be capable of simulating both runoff and groundwater flow conditions on a karst system and also easily adapt to their natural conditions.Adapting the proper stochastic model to the karst groundwater flow conditions offers the possibility to obtain accurate short term predictions, thus contributing to rational groundwater resources exploitation and management planning
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Chen, Gang, Shiguang Xu, Chunxue Liu, Lei Lu, and Liang Guo. "Groundwater flow simulation and its application in GaoSong ore field, China." Journal of Water and Climate Change 10, no. 2 (September 14, 2018): 276–84. http://dx.doi.org/10.2166/wcc.2018.182.
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Abstract Mine water inrush is one of the important factors threatening safe production in mines. The accurate understanding of the mine groundwater flow field can effectively reduce the hazards of mine water inrush. Numerical simulation is an important method to study the groundwater flow field. This paper numerically simulates the groundwater seepage field in the GaoSong ore field. In order to ensure the accuracy of the numerical model, the research team completed 3,724 field fissure measurements in the study area. The fracture measurement results were analyzed using the GEOFRAC method and the whole-area fracture network data were generated. On this basis, the rock mass permeability coefficient tensor of the aquifer in the study area was calculated. The tensor calculation results are used in the numerical model of groundwater flow. After calculation, the obtained numerical model can better represent the groundwater seepage field in the study area. In addition, we designed three different numerical models for calculation, mainly to explore the influence of the tensor assignment of permeability coefficient on the calculation results of water yield of the mine. The results showed that irrational fathom tensor assignment would cause a significant deviation in calculation results.
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Seleznev, Vadim E. "Numerical Adaptation of Pipeline Network Models on Measurement Archive." ISRN Applied Mathematics 2014 (February 9, 2014): 1–6. http://dx.doi.org/10.1155/2014/146591.
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We propose an adaptation method for gas dynamic pipeline network models to enable credible representation of actual properties of real simulation objects. The presentation is illustrated by fitting equivalent pipeline section roughnesses used in the models to accommodate the influence of flow resistance on gas transport parameters. The method is based on the setting up and solution of a series of special parametric identification problems based on a limited set of field measurement data at local (in space) network points. This method can be used by specialists in mathematical modeling of gas transport systems to solve practical parametric identification problems.
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Rabemaharitra, Tahirinandraina Prudence, Yanhong Zou, Zhuowei Yi, Yong He, and Umair Khan. "Optimized Pilot Point Emplacement Based Groundwater Flow Calibration Method for Heterogeneous Small-Scale Area." Applied Sciences 12, no. 9 (May 6, 2022): 4648. http://dx.doi.org/10.3390/app12094648.
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Groundwater flow modeling in a small-scale area requires practical techniques to obtain high accuracy results. The effectiveness of the model calibration is the most challenging for simulating the hydraulic head. In pursuit of this, we proposed an optimized groundwater flow calibration method based on the pilot point emplacement technique for a 3D small-scale area in this work. Subsequently, two emplacement structures were tested during the experimentation, the regular pilot point placement, and the middle head measurement down gradient (MHMDG) placement with two different densities. The parameter estimation (PEST) numerical code applying the kriging interpolation was used to estimate the hydraulic conductivity field by MODFLOW. Moreover, geological SGrid models were chosen for the conceptual model. Thirty-seven observation wells were used for experimental simulations to test the proposed method in a heterogeneous confined aquifer. The result shows that the small-scale modeling was complicated, and the studying area presented a significant heterogeneity in horizontal hydraulic conductivity. The middle head measurement down gradient (MHMDG) pilot point case with the larger density gave the best R-squared 0.901 and minimum residual error of 0.0053 m compared to 0.880 and 0.078 m, respectively, for the regular placement. The calibration accuracy depended on the frequency and the emplacement of the pilot point. Therefore, the initial value should be technically selected to minimize the computation burden. The proposed techniques help to improve the groundwater flow model calibration based on the pilot point methodology for groundwater resources management.
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Aniszewski, Andrzej. "Description and Verification of the Contaminat Transport Models in Groundwater (Theory And Practice)." Archives of Environmental Protection 39, no. 3 (September 1, 2013): 3–21. http://dx.doi.org/10.2478/aep-2013-0021.
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Abstract This paper presents a general overview of 2D mathematical models for both the inorganic and the organic contaminants moving in an aquifer, taking into consideration the most important processes that occur in the ground. These processes affect, to a different extent, the concentration reduction values for the contaminants moving in a groundwater. In this analysis, the following processes have been taken into consideration: reversible physical non-linear adsorption, chemical and biological reactions (as biodegradation/biological denitrification) and radioactive decay (for moving radionuclides). Based on these 2D contaminant transport models it has been possible to calculate numerically the dimensionless concentration values with and without all the chosen processes in relation to both the chosen natural site (piezometers) and the chosen contaminants.In this paper, it has also been possible to compare all the numerically calculated concentration values to the measured concentration ones (in the chosen earlier piezometers) in relation to both the new unpublished measurement series of May 1982 and the new set of parameters used in these 2D contaminant transport models (as practical verification of these models).
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Jha, Madan K., Richard C. Peralta, and Sasmita Sahoo. "Simulation-Optimization for Conjunctive Water Resources Management and Optimal Crop Planning in Kushabhadra-Bhargavi River Delta of Eastern India." International Journal of Environmental Research and Public Health 17, no. 10 (May 18, 2020): 3521. http://dx.doi.org/10.3390/ijerph17103521.
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Water resources sustainability is a worldwide concern because of climate variability, growing population, and excessive groundwater exploitation in order to meet freshwater demand. Addressing these conflicting challenges sometimes can be aided by using both simulation and mathematical optimization tools. This study combines a groundwater-flow simulation model and two optimization models to develop optimal reconnaissance-level water management strategies. For a given set of hydrologic and management constraints, both of the optimization models are applied to part of the Mahanadi River basin groundwater system, which is an important source of water supply in Odisha State, India. The first optimization model employs a calibrated groundwater simulation model (MODFLOW-2005, the U.S. Geological Survey modular ground-water model) within the Simulation-Optimization MOdeling System (SOMOS) module number 1 (SOMO1) to estimate maximum permissible groundwater extraction, subject to suitable constraints that protect the aquifer from seawater intrusion. The second optimization model uses linear programming optimization to: (a) optimize conjunctive allocation of surface water and groundwater and (b) to determine a cropping pattern that maximizes net annual returns from crop yields, without causing seawater intrusion. Together, the optimization models consider the weather seasons, and the suitability and variability of existing cultivable land, crops, and the hydrogeologic system better than the models that do not employ the distributed maximum groundwater pumping rates that will not induce seawater intrusion. The optimization outcomes suggest that minimizing agricultural rice cultivation (especially during the non-monsoon season) and increasing crop diversification would improve farmers’ livelihoods and aid sustainable use of water resources.
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Regnier, P., P. Jourabchi, and C. P. Slomp. "Reactive-Transport modeling as a technique for understanding coupled biogeochemical processes in surface and subsurface environments." Netherlands Journal of Geosciences - Geologie en Mijnbouw 82, no. 1 (April 2003): 5–18. http://dx.doi.org/10.1017/s0016774600022757.
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AbstractReactive-transport models contribute significantly to the field of modern geosciences. A general mathematical approach to solving models of complex biogeochemical systems is introduced. It is argued that even though mathematical models for reactive-transport simulations can be developed at various levels of approximation, the approach for their construction and application to the various compartments of the hydrosphere is fundamentally the same. The workings of coupled transport-reaction systems are described in more detail by means of examples, which demonstrate the similarities in the approach. Three models of the carbon dynamics in redox-stratified environments are compared: porous media flow problems in a coastal sediment and in a contaminated groundwater system; and a surface flow problem in a eutrophic estuary. Considering the interdisciplinary nature of such models, a Knowledge Base System for biogeochemical processes is proposed. Incorporation of the proposed knowledge base in an appropriate modeling framework, such as the Biogeochemical Reaction Network Simulator, proves an effective approach to the modeling of complex natural systems. This methodology allows for construction of multi-component reactive-transport models applicable to a wide range of problems of interest to the geoscientist.
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Kolditz, Olaf, Jens-Olaf Delfs, Claudius Bürger, Martin Beinhorn, and Chan-Hee Park. "Numerical analysis of coupled hydrosystems based on an object-oriented compartment approach." Journal of Hydroinformatics 10, no. 3 (May 1, 2008): 227–44. http://dx.doi.org/10.2166/hydro.2008.003.
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In this paper we present an object-oriented concept for numerical simulation of multi-field problems for coupled hydrosystem analysis. Individual (flow) processes modelled by a particular partial differential equation, i.e. overland flow by the shallow water equation, variably saturated flow by the Richards equation and saturated flow by the groundwater flow equation, are identified with their corresponding hydrologic compartments such as land surface, vadose zone and aquifers, respectively. The object-oriented framework of the compartment approach allows an uncomplicated coupling of these existing flow models. After a brief outline of the underlying mathematical models we focus on the numerical modelling and coupling of overland flow, variably saturated and groundwater flows via exchange flux terms. As each process object is associated with its own spatial discretisation mesh, temporal time-stepping scheme and appropriate numerical solution procedure. Flow processes in hydrosystems are coupled via their compartment (or process domain) boundaries without giving up the computational necessities and optimisations for the numerical solution of each individual process. However, the coupling requires a bridging of different temporal and spatial scales, which is solved here by the integration of fluxes (spatially and temporally). In closing we present three application examples: a benchmark test for overland flow on an infiltrating surface and two case studies – at the Borden site in Canada and the Beerze–Reusel drainage basin in the Netherlands.
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Hoc, Ryszard, Andrzej Sadurski, and Zenon Wiśniowski. "A groundwater flow model for the Wolin Island area, including glaciotectonic deformation." Geologos 24, no. 3 (December 1, 2018): 207–16. http://dx.doi.org/10.2478/logos-2018-0021.
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Abstract During the construction of mathematical models for mapping hydrogeological conditions it is necessary to apply simplifications, both in the geological structure and in hydrogeological parameters used. The present note discusses problems surrounding the mapping of glaciotectonic disturbances that occur in the northern part of Wolin Island (northwest Poland). For this part of the island, a direct outflow of groundwater towards the Baltic Sea basin has been determined on the basis of geophysical survey results. An important feature in the hydrogeological conditions here is the isolation of groundwater from both the Baltic Sea and Szczecin Lagoon by clay with a Cretaceous xenolith. Such a geological structure explains the presence of perched water at considerable heights in zones close to the cliffs, without any significant hydraulic connection with surrounding reservoirs. Hydrogeological conditions of Wolin Island have been modelled using the Visual MODFLOW package v.4.2. In the vertical section, these conditions can be simplified to one aquifer (Pleistocene-Holocene), in which two aquifers can be distinguished. In a large part of the island, these remain in mutual hydraulic contact: layer I – upper, with an unconfined aquifer, and layer II – lower, with a confined aquifer, locally an unconfined one. The schematisation of hydrogeological conditions adopted here has allowed to reproduce present groundwater dynamics in the study area.
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Jablonská, Jana, and Milada Kozubková. "Evaluation of the Characteristics of the Control Valves." MATEC Web of Conferences 328 (2020): 03011. http://dx.doi.org/10.1051/matecconf/202032803011.
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When designing pipeline networks, the knowledge of loss coefficient respectively resistance coefficient when flowing through various types of fluids through hydraulic elements, e.g. control valves, which are often used in the engineering and energy industry. Their specification is performed mainly experimentally. However, there are applications where the experimental approach of their determination is unrealistic and then mathematical methods can be considered. The article presents a methodology for determining the static characteristics of the DN25 control valve for different opening. The measurement of the characteristics was performed with an incompressible flowing medium - water and with a compressible flowing medium - air. Subsequently, a comparison of measurement and evaluation of loss and flow coefficients was performed. The measured values will be further used to verify the results of modelling and to precisely define mathematical models, so that the models can be subsequently used at vapour flow, where the experimental method of determination is difficult. Frequent applications are found in the flow of saturated and superheated vapour through control valves.
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KOWALÓW, Mariusz, Marta CHRYŚCINA, and Małgorzata WRÓBEL-HEN. "AN EXAMPLE OF THE APPLICATION OF A FILTRATION MODEL TO THE PREDICTION OF THE INFLUENCE OF A DEEP-FOUNDED BUILDING ON GROUNDWATER LEVEL CHANGES." Biuletyn Państwowego Instytutu Geologicznego 471 (October 1, 2018): 73–80. http://dx.doi.org/10.5604/01.3001.0012.5049.
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Nowadays, for economical aspect, most of large cubature objects are constructed with underground storeys or car park areas. During the planning phase, it is important to design an optimal, economical and safe dewatering system and technical solutions aimed to eliminate the influence of underground structure on groundwater levels in the neighbourhood. Mathematical modelling of groundwater filtration allows creating a prognosis of excavation dewatering process and influence of new buildings on groundwater levels in subject areas during both execution and operation of structure. The paper presents an example of groundwater filtration modelling for a shopping mall in the centre of Budapest, using SPRING software. The project includes the construction of a large building with an underground story for cars. With filtration models, it was possible to assess the changes in groundwater flow fields caused by projected structure and its excavation dewatering system and the prognosis of groundwater levels around the building, taking into consideration the influence of the flood wave from the Danube on groundwater filtration in the investment area. Based on modelling results the suitable technical solutions were proposed, which allow limiting the effect on the surrounding buildings and the potential changes of water levels in the investment area.
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Liffman, Kurt, Ilija D. Šutalo, Anh Bui, Michael M. D. Lawrence-Brown, and James B. Semmens. "Experimental Measurement and Mathematical Modeling of Pulsatile Forces on a Symmetric, Bifurcated Endoluminal Stent Graft Model." Vascular 17, no. 4 (August 1, 2009): 201–9. http://dx.doi.org/10.2310/6670.2009.00036.
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The objective of this study was to measure the pulsatile forces acting on a symmetric, bifurcated endoluminal stent graft to validate a computational fluid dynamics (CFD) and analytic model so that they can be used for various graft dimensions. We used a load cell to measure the force owing to the movement of an acrylic model of a bifurcated stent graft under pulsatile flow. This was then simulated with a CFD and analytic model. The main features of the experimental pulsatile force data and the CFD results were consistent. The results showed that the total force was proportional to the inlet pressure cycle. The force rose from 3.32 N at 130 mm Hg systolic to 17.5 N at 250 mm Hg systolic pressure. For the more variable regions of the flow, the experimentally measured forces lagged the computational and analytic results. The CFD and analytic models provide approximate descriptions for the forces acting on a bifurcated stent graft subjected to pulsatile flow. Such models should be of assistance to designers of endoluminal stent grafts.
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Han, Feng, Chun Cheng Zuo, Hang Zhu, Wen Fu Wu, and Chun Shan Liu. "The Establish of Digital Simulation System on Continuous Cross-Flow Dryer." Advanced Materials Research 430-432 (January 2012): 1759–63. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.1759.
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Drying plays an important role in the post-harvesting process of grain, and the quality of the corn after drying has received an increasing concern. The mathematical model of grain drying plays an essential role in developing grain dryer structure and obtaining the drying technological parameters. Furthermore, an accurate mathematical model is a reference for automated control during drying process. In this paper, using mathematical models and quality model of the corn drying process, a digital simulation of corn drying machine system based on a virtual instrument was established for 5HSZ dryer. Finally, an on-line measurement and automated control software of grain parameters were developed providing the changes of moisture, temperature, humidity, and germination rate in the process of drying. The experimental results show that the simulation result is valid, which has practical merit of operation and technical optimization of dryer.
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Banton, O., D. Côté, and M. Trudelle. "Détermination au champ de la conductivité hydraulique saturée à l'aide de l'infiltromètre à charge constante de Côté: théorie et approximations mathématiques." Canadian Journal of Soil Science 71, no. 1 (February 1, 1991): 119–26. http://dx.doi.org/10.4141/cjss91-010.
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Saturated hydraulic conductivity is one of the most difficult physical parameters of soil to measure. The most accurate methods are those used in the field in the presence of a groundwater table. However, in many cases, these cannot be used, primarily when no groundwater table is present. The Côté constant head infiltrometer method proves useful in such cases, because the measurement is made on soil which is not necessarily saturated beforehand. The constant head of water used by the infiltrometer is low (3.5 cm), and so representative of precipitation and irrigation conditions. The device (which is 10 cm in diameter) performs the measurement on a large area of soil (roughly 200 cm2), and can therefore integrate varying heterogeneity and macroporosity, rendering the measurement more reliable and representative. The quantity of water needed for a measurement is about 1 L, making operation in the field easier. The Côté constant head infiltrometer is an unsophisticated device which is easy to use. Different mathematical approximations of the saturated flow of water around the infiltometer are described according to the various forms of flow taken into account. The corresponding coefficients may be used to quickly determine this parameter with a high level of confidence. However, one problem and some potential sources of error remain in the evaluation of hydraulic conductivity in the field, due principally to cases in which the soil is not totally saturated, to compaction or smoothing of the hole during digging, and to the variability of the parameter on the site. Key words: Hydraulic conductivity, infiltrometer, permeameter
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Kurnatowski, Jacek. "The influence of the measurement errors on the Brutsaefrt and Nieber analysis of flow recession curves." ITM Web of Conferences 23 (2018): 00022. http://dx.doi.org/10.1051/itmconf/20182300022.
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The paper presents the problem of mathematical form of the hydrological recession in rivers when using conceptual models to describe the catchment behavior. One of the well-known ways of this analysis is the Brutsaert and Nieber method which is based on graphical comparison of flow values and its derivatives. It has been proved that the classical interpretation of these results does not reflect the possible influence of measurement errors which strongly affects the flow derivatives values.
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Cai, Jin, Xiangwei Kong, and Mingzhu Yu. "Mathematical Modeling of Sintering Air Leakage through Holes." Energies 15, no. 12 (June 8, 2022): 4224. http://dx.doi.org/10.3390/en15124224.
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The air leakage in sintering machines affects the technological and economic indexes of the sintering process. It is of great significance to monitor and estimate the key areas. Mathematical models of sintering air leakage through holes in the steady-state process are given based on the fluid mechanics to predict the flow rate and effect on the key area. It was found that the hole model is the application of constant orifice outflow in the computation of sintering air leakage. The counter-flow bed model is suitable for predicting the flow rate through a complete break in sintering wind boxes. Furthermore, This paper proposes a new hole–bed generalized model to cover all the possible hole diameters for further high-precision application. The model connects the leakage hole diameter with the sintering process for the first time and establishes their coupling relationship. The pressure state in the sintering system depends on the ratio of the leakage hole area to the sintering bed area. The proposed fast estimation models are a step forward in developing more precise and powerful calculation tools to foresee the effects and consequences of sintering air leakage. It has a good prospect for reducing and replacing complex manual measurement and bringing some insight into the state of the art that could be improved in the future.
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García-Rodríguez, Luz del Carmen, Juan Prado-Olivarez, Rosario Guzmán-Cruz, Martín Antonio Rodríguez-Licea, Alejandro Israel Barranco-Gutiérrez, Francisco Javier Perez-Pinal, and Alejandro Espinosa-Calderon. "Mathematical Modeling to Estimate Photosynthesis: A State of the Art." Applied Sciences 12, no. 11 (May 30, 2022): 5537. http://dx.doi.org/10.3390/app12115537.
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Photosynthesis is a process that indicates the productivity of crops. The estimation of this variable can be achieved through methods based on mathematical models. Mathematical models are usually classified as empirical, mechanistic, and hybrid. To mathematically model photosynthesis, it is essential to know: the input/output variables and their units; the modeling to be used based on its classification (empirical, mechanistic, or hybrid); existing measurement methods and their invasiveness; the validation shapes and the plant species required for experimentation. Until now, a collection of such information in a single reference has not been found in the literature, so the objective of this manuscript is to analyze the most relevant mathematical models for the photosynthesis estimation and discuss their formulation, complexity, validation, number of samples, units of the input/output variables, and invasiveness in the estimation method. According to the state of the art reviewed here, 67% of the photosynthesis measurement models are mechanistic, 13% are empirical and 20% hybrid. These models estimate gross photosynthesis, net photosynthesis, photosynthesis rate, biomass, or carbon assimilation. Therefore, this review provides an update on the state of research and mathematical modeling of photosynthesis.
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Xiao, Xiao, and Lei Chen. "Error analysis system of industrial steam heat flow based on neural network computer simulation." Thermal Science 25, no. 4 Part B (2021): 3149–58. http://dx.doi.org/10.2298/tsci2104149x.
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The paper focuses on the analysis of the neural network mathematical model for temperature and pressure compensation in steam flow measurement, summarizes two types of compensation models suitable for DCS configuration, and introduces the realization of steam flow measurement in ABB Industrial TDCS configuration ways and methods of temperature and pressure compensation. At the same time, the paper uses the scientific neural network intelligent model control method to analyze, optimize, configure and manage the information, improve the operation and management level of the steam system, and realize the optimized operation of the steam system, so as to achieve the purpose of energy saving and consumption reduction.
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Long, A. J. "RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow Model (v1.11)." Geoscientific Model Development Discussions 7, no. 5 (September 9, 2014): 5919–63. http://dx.doi.org/10.5194/gmdd-7-5919-2014.
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Abstract. The Rainfall-Response Aquifer and Watershed Flow Model (RRAWFLOW) is a lumped-parameter model that simulates streamflow, springflow, groundwater level, solute transport, or cave drip for a measurement point in response to a system input of precipitation, recharge, or solute injection. The RRAWFLOW open-source code is written in the R language and is included in the Supplement to this article along with an example model of springflow. RRAWFLOW includes a time-series process to estimate recharge from precipitation and simulates the response to recharge by convolution; i.e., the unit hydrograph approach. Gamma functions are used for estimation of parametric impulse-response functions (IRFs); a combination of two gamma functions results in a double-peaked IRF. A spline fit to a set of control points is introduced as a new method for estimation of nonparametric IRFs. Other options include the use of user-defined IRFs and different methods to simulate time-variant systems. For many applications, lumped models simulate the system response with equal accuracy to that of distributed models, but moreover, the ease of model construction and calibration of lumped models makes them a good choice for many applications. RRAWFLOW provides professional hydrologists and students with an accessible and versatile tool for lumped-parameter modeling.
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Yugendar, Poojari, and K. V. R. Ravishankar. "Analysis of Crowd Flow Parameters Using Artificial Neural Network." Transport and Telecommunication Journal 19, no. 4 (December 1, 2018): 335–45. http://dx.doi.org/10.2478/ttj-2018-0028.
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Abstract Research scientists have been developing mathematical tools to detect objects, recognize objects and actions, and discover behaviours and events to human abilities. In all these efforts, the understanding of human actions is of a special interest for both application and research purposes. In this study, crowd flow parameters are analysed by considering linear and non linear relationships between stream flow parameters using conventional and soft computing approach. Deterministics models like Greenshield and Underwood were applied in the study to describe flow characteristics. A non-linear model based on Artificial Neural Network (ANN) approach is also used to build a relationship between different crowd flow parameters and compared with the other deterministic models. ANN model gave good results based on accuracy measurement to deterministic models because of their self-processing and intelligent behaviour. Mean absolute error (MAE) and root mean square error (RMSE) values for the best fitted ANN model are less than those for the other models. ANN model gives better performance in fitness of model and future prediction of flow parameters.
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Jablonská, Jana, Milada Kozubková, and Marian Bojko. "Flow of Oil and Water through the Nozzle and Cavitation." Processes 9, no. 11 (October 28, 2021): 1936. http://dx.doi.org/10.3390/pr9111936.
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Today, the correct understanding of the issue of oil and water cavitation is important due to the growing demands on working conditions in hydraulic systems (pressure and flow rate). This article deals with the measurement and subsequent mathematical modeling of cavitation in a convergent-divergent nozzle of circular cross-section. Cavitation depends on the physical properties of the flowing medium as a function of temperature. Usually, cavitation in water is defined by a two-phase flow of water and vapor, but the air contained in the water significantly affects cavitation. There is usually no vapor cavitation in the oil. Far more often, cavitation in oil is caused by the air it contains. For comparison, cavitation in water and oil was generated in experiments with an identical nozzle. The measurement was used to define boundary conditions in mathematical models and to verify simulations. The problem of cavitation was solved by three variants of multiphase flow, single-phase flow (water, oil), two-phase flow (water–vapor, oil–air) and three-phase flow (water–vapor–air, oil–vapor–air). A turbulent model with cavitation was used for all variants. The verification of simulations shows that for water cavitation it is necessary to use a three-phase model (water, vapor, air) and for oil cavitation a two-phase model (oil, air) is sufficient. The measurement results confirm the importance of the air phase in modeling cavitation in both water and oil.
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Dong, Yu Bo. "Discussion on Urban Road Traffic Congestion Algorithm for Automatically Determining." Advanced Materials Research 926-930 (May 2014): 3790–93. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.3790.
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Compared with the expressway, most of the traffic flow in urban road network can be denoted as interrupted traffic flow. Based on the current employed equipment for traffic flow collection and traffic signal control in urban roads, different types of traffic flow in urban roads are analyzed with the traffic flow arrival/departure model in transportation engineering. Mathematical models complying with traffic flow changes are utilized to match the traffic flow in both entry and exit road blocks, thus, enabled the automatic detection of traffic incident. This algorithm provides a measurement for the automatic judgment of urban road congestion and the expansion utility of intelligent transportation facilities in urban areas.
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Ke, Xianmin, Wei Wang, Jinlong Li, Qiming Sun, Lulu Lian, Xiangdong Xu, and Qiaofen Lyu. "In-situ pumping tests and numerical simulations of seepage wells in the Yellow River valley, China." Water Supply 22, no. 2 (October 5, 2021): 1459–73. http://dx.doi.org/10.2166/ws.2021.340.
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Abstract Seepage wells that can convert surface water into groundwater are often constructed near river valleys to obtain more water and lead to smaller drawdown compared with traditional wells. Seepage wells have been widely used, whilst the groundwater and river-level variations caused by seepage wells are still unclear, and numerical models are rarely verified due to the lack of in-situ observational data, which may lead to results that are quite different from the actual conditions. To address those limitations, a large-scale pumping test was carried out near the Yellow River valley in China and a coupled seepage–pipe flow model was established using the exchange yield between the aquifer and pipe as the coupling key in this research. The coupled model was evaluated with in-situ measurement. The field observation showed that both the river and groundwater had a positive response to the pumping of the seepage wells. The simulation results indicated that our model can well estimate the pumping rate and drawdown with root-mean-square deviations of 158.235 m3/d and 0.766 m, respectively. Further, it is also found that the groundwater showed the obvious characteristics of three-dimensional flow under the influence of seepage wells and the maximum drawdown should be less than 15 m to ensure exploitation efficiency. These findings provide important information that can guide the design and construction of seepage wells to improve the rational exploitation of groundwater.
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Long, A. J. "RRAWFLOW: Rainfall-Response Aquifer and Watershed Flow Model (v1.15)." Geoscientific Model Development 8, no. 3 (March 30, 2015): 865–80. http://dx.doi.org/10.5194/gmd-8-865-2015.
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Abstract. The Rainfall-Response Aquifer and Watershed Flow Model (RRAWFLOW) is a lumped-parameter model that simulates streamflow, spring flow, groundwater level, or solute transport for a measurement point in response to a system input of precipitation, recharge, or solute injection. I introduce the first version of RRAWFLOW available for download and public use and describe additional options. The open-source code is written in the R language and is available at http://sd.water.usgs.gov/projects/RRAWFLOW/RRAWFLOW.html along with an example model of streamflow. RRAWFLOW includes a time-series process to estimate recharge from precipitation and simulates the response to recharge by convolution, i.e., the unit-hydrograph approach. Gamma functions are used for estimation of parametric impulse-response functions (IRFs); a combination of two gamma functions results in a double-peaked IRF. A spline fit to a set of control points is introduced as a new method for estimation of nonparametric IRFs. Several options are included to simulate time-variant systems. For many applications, lumped models simulate the system response with equal accuracy to that of distributed models, but moreover, the ease of model construction and calibration of lumped models makes them a good choice for many applications (e.g., estimating missing periods in a hydrologic record). RRAWFLOW provides professional hydrologists and students with an accessible and versatile tool for lumped-parameter modeling.
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Czyżewicz, Jacek, Piotr Jaskólski, Paweł Ziemiański, Marian Piwowarski, Mateusz Bortkiewicz, Krzysztof Laszuk, Ireneusz Galara, Marta Pawłowska, and Karol Cybulski. "Towards Designing an Innovative Industrial Fan: Developing Regression and Neural Models Based on Remote Mass Measurements." Energies 15, no. 7 (March 25, 2022): 2425. http://dx.doi.org/10.3390/en15072425.
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This article presents the process of the construction and testing a remote, fully autonomous system for measuring the operational parameters of fans. The measurement results obtained made it possible to create and verify mathematical models using linear regression and neural networks. The process was implemented as part of the first stage of an innovative project. The article presents detailed steps of constructing a system to collect and process measurement data from fans installed in actual operating conditions and the results of analysis of this data. In particular, a measurement infrastructure was developed, defined, and implemented. Measuring equipment was mounted on selected ventilation systems with relevant fans. Systems were implemented that allowed continuous measurement of ventilation system parameters and remote transmission of data to a server where it was regularly analysed and selected for use in the process of modelling and diagnostics. Pearson’s correlation analysis for p < 0.05 indicated that all seven parameters (suction temperature, discharge temperature, suction pressure, current consumption, rotational speed, humidity, and flow) were significantly correlated with efficiency (p < 0.001). A satisfactory level of correlation between the selected parameters measured in actual conditions and the characteristics of the fan and the ventilation system was experimentally verified. This was determined by finding 4 statistically significant parameters at a confidence level of 95%. This allowed the creation of two mathematical models of the fan system and the ventilation system using linear regression and neural networks. The linear regression model showed that the suction temperature, discharge temperature, and air humidity did not affect the fan efficiency (they are statistically insignificant, p > 0.05). The neural model, which considered all measured parameters, achieved the same accuracy as the model based on four significant parameters: suction pressure, current consumption, rotational speed, and flow.
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Tran, Hoang, Elena Leonarduzzi, Luis De la Fuente, Robert Bruce Hull, Vineet Bansal, Calla Chennault, Pierre Gentine, Peter Melchior, Laura E. Condon, and Reed M. Maxwell. "Development of a Deep Learning Emulator for a Distributed Groundwater–Surface Water Model: ParFlow-ML." Water 13, no. 23 (December 1, 2021): 3393. http://dx.doi.org/10.3390/w13233393.
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Integrated hydrologic models solve coupled mathematical equations that represent natural processes, including groundwater, unsaturated, and overland flow. However, these models are computationally expensive. It has been recently shown that machine leaning (ML) and deep learning (DL) in particular could be used to emulate complex physical processes in the earth system. In this study, we demonstrate how a DL model can emulate transient, three-dimensional integrated hydrologic model simulations at a fraction of the computational expense. This emulator is based on a DL model previously used for modeling video dynamics, PredRNN. The emulator is trained based on physical parameters used in the original model, inputs such as hydraulic conductivity and topography, and produces spatially distributed outputs (e.g., pressure head) from which quantities such as streamflow and water table depth can be calculated. Simulation results from the emulator and ParFlow agree well with average relative biases of 0.070, 0.092, and 0.032 for streamflow, water table depth, and total water storage, respectively. Moreover, the emulator is up to 42 times faster than ParFlow. Given this promising proof of concept, our results open the door to future applications of full hydrologic model emulation, particularly at larger scales.