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Kitrattana, Borirak, Satha Aphornratana, and Tongchana Thongtip. "One dimensional steam ejector model based on real fluid property." Thermal Science and Engineering Progress 25 (October 2021): 101016. http://dx.doi.org/10.1016/j.tsep.2021.101016.
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Ionescu, C. M., I. R. Birs, D. Copot, C. I. Muresan, and R. Caponetto. "Mathematical modelling with experimental validation of viscoelastic properties in non-Newtonian fluids." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2172 (May 11, 2020): 20190284. http://dx.doi.org/10.1098/rsta.2019.0284.
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The paper proposes a mathematical framework for the use of fractional-order impedance models to capture fluid mechanics properties in frequency-domain experimental datasets. An overview of non-Newtonian (NN) fluid classification is given as to motivate the use of fractional-order models as natural solutions to capture fluid dynamics. Four classes of fluids are tested: oil, sugar, detergent and liquid soap. Three nonlinear identification methods are used to fit the model: nonlinear least squares, genetic algorithms and particle swarm optimization. The model identification results obtained from experimental datasets suggest the proposed model is useful to characterize various degree of viscoelasticity in NN fluids. The advantage of the proposed model is that it is compact, while capturing the fluid properties and can be identified in real-time for further use in prediction or control applications. This article is part of the theme issue ‘Advanced materials modelling via fractional calculus: challenges and perspectives’.
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Li, Chang He, Li Li Wang, and Guo Yu Liu. "Mathematical Model of Hydrodynamic Fluid Pressure on Smooth and Real Surface." Advanced Materials Research 135 (October 2010): 429–34. http://dx.doi.org/10.4028/www.scientific.net/amr.135.429.
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Conventional method of flood delivering coolant fluid by a nozzle in order to achieve high process performance. However, hydrodynamic fluid pressure can be generated ahead of the contact zone due to the wedge effect between wheel peripheral surface and work surface. In the paper, theoretical hydrodynamic pressure modeling were presented for flow of coolant fluid through the grinding zone in flood delivery grinding using smooth and roughness surface grinding wheel respectively. The simulation results show that the hydrodynamic pressure was proportion to grinding wheel velocity, and inverse proportion to the minimum gap between wheel and work surface and the maximum pressure value was generated just in the minimum gap region in which higher fluid pressure gradient occuring. It can also be concluded the surface roughness of grinding wheel and workpiece makes the contact zone’s hydrodynamic pressure rough and unstable, i.e. the value curve considering roughness is not smooth, leading to the micro-elastohydrodynamic lubrication phenomenon.
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Jondahl, Morten Hansen, and Håkon Viumdal. "Developing ultrasonic soft sensors to measure rheological properties of non-Newtonian drilling fluids." tm - Technisches Messen 86, no. 12 (November 18, 2019): 744–57. http://dx.doi.org/10.1515/teme-2019-0039.
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AbstractSurveillance of the rheological properties of drilling fluids is crucial when drilling oil wells. The prevailing standard is lab analysis. The need for automated real-time measurements is, however, clear.Ultrasonic measurements in non-Newtonian fluids have been shown to exhibit a non-linear relationship between the acoustic attenuation and rheological properties of the fluids. In this paper, three different fluid systems are examined. They are diluted to give a total of 33 fluid sets and their ultrasonic and rheological properties are measured. Machine learning models are applied to develop soft sensors that are capable of estimating the rheological properties based on the ultrasonic measurements. This study explores three different machine learning model types and, extensive training and tuning of the models is carried out. The best model types that show good results and the potential to develop a real-time sensor system suitable for use in oil & gas drilling process automation are selected.
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Xiong, Fansheng, and Wen-An Yong. "Learning stable seismic wave equations for porous media from real data." Geophysical Journal International 230, no. 1 (February 25, 2022): 349–62. http://dx.doi.org/10.1093/gji/ggac082.
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SUMMARY This work presents a machine-learning-based framework to determine unknown coefficients in seismic wave equations for porous media saturated with fluids by using real data as labels, which are velocities of P and S waves. The coefficients are functions of basic rock physics parameters. By using this framework, the trained neural networks incorporate certain mathematical and physical constraints on the coefficients. Working on a single-fluid model, we train the networks with synthetic as well as real data sets. The prediction results show that the learned model is inherently stable, has good physical properties and can accurately predict synthetic data as well as real logging data of shale reservoirs with relative mean square errors less than 5 per cent. They also demonstrate that the wave propagation phenomenon corresponding to the logging data can be well described with the single-fluid model.
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Chirkov, A. Yu, K. S. Egorov, K. B. Ganeev, and T. R. Zuev. "Model of a real cycle of a power installation with a real-gas working fluid." Journal of Physics: Conference Series 1368 (November 2019): 042083. http://dx.doi.org/10.1088/1742-6596/1368/4/042083.
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Wiśniowski, Rafał, Krzysztof Skrzypaszek, and Przemysław Toczek. "Vom Berg and Hahn–Eyring Drilling Fluid Rheological Models." Energies 15, no. 15 (August 1, 2022): 5583. http://dx.doi.org/10.3390/en15155583.
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This article presents rheological models of fluids used in the drilling practice. It discusses the principles of determining drilling fluid rheological parameters based on data acquired from measurements by means of viscometers used in the drilling practice. The authors propose the application of the three-parameter Vom Berg and Hahn–Eyring models not used in the drilling industry so far. Necessary relationships have been developed for these models, which enable the determination of rheological parameters. In order to account for the influence of different flow conditions on the value of drilling fluid rheological parameters, the approach proposing the determination of rheological parameters of a given three-parameter model separately for low shear rates and high shear rates has been suggested. A practical application of the methodology proposed in this paper for determining the rheological parameters of the three-parameter Vom Berg and Hahn–Eyring models is presented using real drilling fluids as an example. Using the author’s methodology for determining the optimum rheological model, called Rheosolution, described earlier in the paper “Selection of Suitable Rheological Model for Drilling Fluid Using Applied Numerical Methods”, published in Energies 2020, 13, 3192, and laboratory tests performed for this work (for cement slurries according to API standards), a strong correlation of the Vom Berg model and, in particular, the Hahn–Eyring model for such drilling fluids was demonstrated.
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Bair, Scott, and Farrukh Qureshi. "The Generalized Newtonian Fluid Model and Elastohydrodynamic Film Thickness." Journal of Tribology 125, no. 1 (December 31, 2002): 70–75. http://dx.doi.org/10.1115/1.1504086.
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The nature of real shear-thinning in elastohydrodynamic contacts is well-known from both experimental measurement and nonequilibrium molecular dynamics to follow a power-law. Shear-thinning will affect the film thickness when the Newtonian limit is low enough to occur in the inlet zone (less than about 1 MPa shear stress). Then kinetic theory tells us that film thinning should occur for molecular weight greater than 2000 kg/kmol. We present a review of generalized Newtonian models, flow curves for real lubricants and comparison of calculated and measured film thickness. The calculations utilize measurable liquid behavior, in contrast to most previous work.
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Yamada, M., and Y. Saiki. "Chaotic properties of a fully developed model turbulence." Nonlinear Processes in Geophysics 14, no. 5 (September 25, 2007): 631–40. http://dx.doi.org/10.5194/npg-14-631-2007.
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Abstract. Shell models of turbulence have been employed as toy models which, in their chaotic states, show statistical properties similar to real fluid turbulence, including Kolmogorov energy spectrum and intermittency. These models are interesting because, at the present stage, it is still quite difficult or almost impossible to study relations between those traditional statistical properties and the structure of the chaos underlying the real fluid turbulence because of huge dimension of the chaotic attractor. In this paper we will give a brief review on the chaotic properties of a shell model (GOY model), with emphasis on its Lyapunov spectrum and unstable periodic orbits, in relation to the Kolmogorov scaling law of the turbulence.
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Zhu, Guoming (George), and Xiang Chen. "Model-Based Engine Control." Mechanical Engineering 137, no. 12 (December 1, 2015): S2—S6. http://dx.doi.org/10.1115/1.2015-dec-6.
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Abstract This article focuses on control-oriented engine modeling and model-based engine control techniques. The engine modeling research is centered on the engine combustion process. Multi-zone, three dimensional computational fluid dynamics (CFD) models, with detailed chemical kinetics are able to precisely describe the thermodynamics, fluid and flow dynamics, heat transfer, and pollutant formation of the combustion process. The simplified one-dimensional combustion models have also been implemented into commercial codes such as GT-Power and Wave. However, these high fidelity models cannot be used for model-based control since they are too complicated to be used for real-time computing. Crank-resolved engine air handling system modeling is also important for describing the in-cylinder charge-mixing process. Therefore, for model-based control and real-time hardware-in-the-loop simulations, it is necessary to have a crank-resolved engine model with its complexity intermediate between the time-based mean-value and one-dimensional CFD models.
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Dupuy, P. M. M., M. Fernandino, H. F. F. Svendsen, and R. Westra. "CO2: One-Component Two-Phase System as Model Fluid for High-Pressure Hydrocarbon Systems." SPE Journal 16, no. 02 (December 23, 2010): 482–88. http://dx.doi.org/10.2118/139606-pa.
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Summary In the process of performing either scientific experiments or research and development related to the design and optimization of high-pressure liquid-from-gas separator units, both laboratory experiments and tests in prototypes are needed. In order to emulate the low interfacial tensions often experienced in high-pressure hydrocarbon systems, the use of carbon dioxide (CO2) as model fluid is studied. This paper describes how the CO2 system behaves at saturation conditions. It describes this system and compares it with traditional laboratory systems and real fluids (from the field). CO2 at saturation pressure under normal temperatures presents an interesting system with low interfacial tension, below 3 mN/m, while the liquid/gas-density ratio is approximately 3. The availability of the fluid (CO2) in research centers and academia is high. When planning a matrix of experiments as part of a database of reproducible laboratory fluids, the present system is an independent base vector ideal for studying the high-Weber/low-Reynolds-number regime. This paper shows how a dispersed CO2-droplet phase, representative of a hydrocarbon-gas/condensate system, can be achieved in the laboratory and used for studying collision outcomes. Results show that it is possible to obtain streams of droplets for droplet experiments. The mean diameter in the studied regime with the particular nozzle used was on the order of 100 µm, while the smallest droplets possible to track with the presented technique were approximately 40 µm. Droplet/wall-collision experiments were focused in this work. Both coalescence and bouncing were observed on both dry and wet walls. The absence of real fluid experiments at laboratory conditions generates a lack of basic knowledge about what is happening in real scrubbers. This system is proposed to be representative for a part of the flow-property region of interest in real gas/liquid scrubbers. This basic knowledge is fundamental when designing separation units at high pressures for gas-processing stages such as subsea gas-separation concepts.
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Lehmann, Robert, Arthur Petuchow, Matthias Moullion, Moritz Künzler, Christian Windel, and Frank Gauterin. "Fluid Choice Based on Thermal Model and Performance Testing for Direct Cooled Electric Drive." Energies 13, no. 22 (November 10, 2020): 5867. http://dx.doi.org/10.3390/en13225867.
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In this publication, the cooling fluid for direct oil-cooled electric traction drive is investigated. A dedicated thermal resistance model was developed in order to show the influence of the fluid properties on the continuous performance. For this purpose, the heat transfer parameters are adjusted in the simulation using an exponential approach in order to evaluate the cooling fluid. In a sensitivity study, density, heat capacity, thermal conductivity, and viscosity are investigated. Because viscosity, within the range investigated, shows the largest percentage deviation from the reference fluid, the greatest effect on performance can be seen here. In order to check the plausibility of the calculated results of the thermal simulation, two fluids were chosen for performance testing on a dedicated electro motor cooling (EMC) test. Beyond the investigation of heat transfer, aging of the defined fluid at maximum heat input over several hours is also evaluated. Only slight changes of the fluid properties are detected. This publication presents a thermal model for direct oil-cooled drive trains, which consider fluid properties. Furthermore, the model was tested for plausibility on real hardware.
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MARCONI, STEFAN, BASTIEN CHOPARD, and JONAS LATT. "REDUCING THE COMPRESSIBILITY OF A LATTICE BOLTZMANN FLUID USING A REPULSIVE FORCE." International Journal of Modern Physics C 14, no. 08 (October 2003): 1015–26. http://dx.doi.org/10.1142/s0129183103005157.
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This paper investigates the possibility to reduce the compressibility of lattice Boltzmann fluid models by introducing a repulsive force between nearest neighbor lattice Boltzmann particles. This new interaction is based on the Shan–Chen model. The interest of this approach is that it implements the physical mechanism responsible for the incompressibility of real fluids and retains the natural interpretation of the fluid density and fluid momentum. The new state equation shows that the compressibility factor decreases as the repulsive interaction increases. However, numerical instabilities limit the value of the acceptable repulsion. We investigate several situations, such as the Poiseuille flow with pressure gradient, a static fluid subject to gravity and the Womersley flow to evaluate the benefits of our approach. Globally, the compressibility of lattice Boltzmann fluids can be reduced by a factor of 4.
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Ulvmoen, Marit, Henning Omre, and Arild Buland. "Improved resolution in Bayesian lithology/fluid inversion from prestack seismic data and well observations: Part 2 — Real case study." GEOPHYSICS 75, no. 2 (March 2010): B73—B82. http://dx.doi.org/10.1190/1.3335332.
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We have performed lithology/fluid inversion based on prestack seismic data and well observations from a gas reservoir offshore Norway. The prior profile Markov random field model captures horizontal continuity and vertical sequencing of the lithology/fluid variables. The prior model is also locally adjusted for spatially varying lithology/fluid proportions. The likelihood model is inferred from basic seismic theory and observations in wells. An approximate posterior model is defined, which can be simulated from by an extremely computer-efficient algorithm. The lithology/fluid inversion results are compared to manual interpretations and evaluated by cross validation in one well. Moreover, inversions based on simplified prior models are developed for comparative reasons. Both lithology/fluid realizations and predictions look geologically reasonable. The results seem to reflect general reservoir experience and information provided by the prestack seismic data and well observations. The lithology/fluid proportions appear as geologically plausible and thin elongated lithology/fluid units are identified. The study is made in a 2D cross section, but extension to a full 3D setting is feasible.
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Liu, Naipeng, Di Zhang, Hui Gao, Yule Hu, and Longchen Duan. "Real-Time Measurement of Drilling Fluid Rheological Properties: A Review." Sensors 21, no. 11 (May 21, 2021): 3592. http://dx.doi.org/10.3390/s21113592.
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The accurate and frequent measurement of the drilling fluid’s rheological properties is essential for proper hydraulic management. It is also important for intelligent drilling, providing drilling fluid data to establish the optimization model of the rate of penetration. Appropriate drilling fluid properties can improve drilling efficiency and prevent accidents. However, the drilling fluid properties are mainly measured in the laboratory. This hinders the real-time optimization of drilling fluid performance and the decision-making process. If the drilling fluid’s properties cannot be detected and the decision-making process does not respond in time, the rate of penetration will slow, potentially causing accidents and serious economic losses. Therefore, it is important to measure the drilling fluid’s properties for drilling engineering in real time. This paper summarizes the real-time measurement methods for rheological properties. The main methods include the following four types: an online rotational Couette viscometer, pipe viscometer, mathematical and physical model or artificial intelligence model based on a Marsh funnel, and acoustic technology. This paper elaborates on the principle, advantages, limitations, and usage of each method. It prospects the real-time measurement of drilling fluid rheological properties and promotes the development of the real-time measurement of drilling rheological properties.
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Gao, Zhengwei, Haiou Wang, Kun Luo, Changcheng Song, Chunguang Zhao, Jiangkuan Xing, and Jianren Fan. "Evaluation of real-fluid flamelet/progress variable model for laminar hydrothermal flames." Journal of Supercritical Fluids 143 (January 2019): 232–41. http://dx.doi.org/10.1016/j.supflu.2018.08.014.
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Bagar, Florian, Daniel Scherzer, and Michael Wimmer. "A Layered Particle-Based Fluid Model for Real-Time Rendering of Water." Computer Graphics Forum 29, no. 4 (August 26, 2010): 1383–89. http://dx.doi.org/10.1111/j.1467-8659.2010.01734.x.
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YAGI, Takanobu. "Japanese Model of Future Medicine with Engineering : Fluid Dynamics into Real World." Journal of the Society of Mechanical Engineers 118, no. 1162 (2015): 592–94. http://dx.doi.org/10.1299/jsmemag.118.1162_592.
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Rodriguez, C., Houman B. Rokni, P. Koukouvinis, Ashutosh Gupta, and M. Gavaises. "Complex multicomponent real-fluid thermodynamic model for high-pressure Diesel fuel injection." Fuel 257 (December 2019): 115888. http://dx.doi.org/10.1016/j.fuel.2019.115888.
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Kelkar, A. S., R. L. Mahajan, and R. L. Sani. "Real-Time Physiconeural Solutions for MOCVD." Journal of Heat Transfer 118, no. 4 (November 1, 1996): 814–21. http://dx.doi.org/10.1115/1.2822575.
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This paper presents an integrated physiconeural network approach for the modeling and optimization of a vertical MOCVD reactor. The basic concept is to utilize the solutions obtained from a physical model to build an accurate neural network (NN) model The resulting model has the attractive features of self-adaptiveness and speed of prediction and is an ideal starting tool for process optimization and control. Following this approach, a first-principles physical model for the reactor was solved numerically using the Fluid Dynamics Analysis Package (FIDAP). This transient model included property variation and thermodiffusion effects. Using software developed in house, neural networks were then trained using FIDAP simulations for combinations of process parameters determined by the statistical Design of Experiments (DOE) methodology. The outputs were the average and local deposition rates. It is shown that the trained NN model predicts the behavior of the reactor accurately. Optimum process conditions to obtain a uniform thickness of the deposited film were determined and tested using the physical model. The results demonstrate the power and robustness of NNs for obtaining fast responses to changing input conditions. A procedure for developing equipment models based on physiconeural network models is also described.
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Caruana, Roberta, Luciano Gallazzi, Romano Iazurlo, Maurizio Marcovati, and Manfredo Guilizzoni. "A Multi-Node Lumped Parameter Model Including Gravity and Real Gas Effects for Steady and Transient Analysis of Heat Pipes." Fluids 7, no. 3 (March 16, 2022): 109. http://dx.doi.org/10.3390/fluids7030109.
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This work presents a multi-node lumped parameter model able to predict the steady and transient behavior of capillary heat pipes, taking into account the effects of gravity (orientation angle) and the real gas effects in the vapor modeling. The model was validated against experimental results acquired by Leonardo S.p.A., which were obtained by simulating the behavior of a heat pipe embedded in a chassis cover, subject to seven cycles of transient thermal loading. After the validation, the analysis is focused on the model accuracy when using the ideal and real gas assumptions, using different working fluids (water, ammonia, acetone, HFC134a). The results showed that when using water or ammonia as working fluid, the error in modeling the vapor as an ideal instead of as real gas is negligible, both for the vapor temperatures and pressures predictions. On the contrary, when using acetone or HFC134a as working fluid, modeling the vapor as a real gas leads to a significant increase in the accuracy of the vapor pressure predictions.
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Wolff-Jesse, C., and G. Fees. "Examination of flow behaviour of electrorheological fluids in the flow mode." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 212, no. 3 (May 1, 1998): 159–73. http://dx.doi.org/10.1243/0959651981539370.
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The use of electrorheological (ER) fluids in hydraulic systems has been demonstrated in detailed investigations at the Institute of Fluid Power Transmission and Control (IFAS) [1]. The flow behaviour of this fluid cannot be described reliably. A detailed knowledge of this flow behaviour would enable better ER component design and produce basic information for simulation models. It is therefore important for the practical applications of ER fluids. A detailed comparison is made between existing rheological models, e.g. the Bingham model, and measured values in flow mode to confirm these models and, if possible, to define a material property constant. In addition, a simple model describing the flow behaviour of an ER fluid in the flow mode with the help of a geometrical dependent variable is presented. This variable is derived from measured values and reflects the influence of the gap height and the gap length. A comparison between this function and real measured values gives a very good agreement within the defined sphere and therefore it is a good tool for the design of electrorheological flow resistors.
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DU, JIAPEI, YUHUAN BU, ZHONGHOU SHEN, and XUECHAO CAO. "MAXIMUM PENETRATION DEPTH AND PENETRATION TIME PREDICTING MODEL OF CEMENTING FLUID FLOW THROUGH WELLBORE INTO WEAKLY CONSOLIDATED FORMATION." Fractals 27, no. 08 (December 2019): 1950132. http://dx.doi.org/10.1142/s0218348x19501329.
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A model for predicting the penetration depth and penetration time of cementing fluid through the wellbore into weakly consolidated formations based on the analytical fractal permeability model for power-law fluids considering the particle size of fluid and irreducible water is proposed and verified in this paper. The penetration distance and utilization dosage are related to the properties of cementing fluid and weakly consolidated formations. All of the parameters in the model have clear physical meaning, and no empirical parameter is used in this model. The results show that the cementing fluid tends to migrate to a long distance under a high pressure differential and low flow rate. The maximum penetration time and maximum penetration volume of cementing fluid increases with the increasing of grouting pressure and decreases with the increase in the volume flow rate. Therefore, throughout the cementing operation, the parameters should be adjusted based on the real situation.
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van Wachem, Berend, Thomas Curran, and Fabien Evrard. "Fully Correlated Stochastic Inter-Particle Collision Model for Euler–Lagrange Gas–Solid Flows." Flow, Turbulence and Combustion 105, no. 4 (February 6, 2020): 935–63. http://dx.doi.org/10.1007/s10494-020-00111-7.
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AbstractIn Lagrangian stochastic collision models, a fictitious particle is generated to act as a collision partner, with a velocity correlated to the velocity of the real colliding particle. However, most often, the fluid velocity seen by this fictitious particles is not accounted for in the generation of the fictitious particle velocity, leading to a de-correlation between the fictitious particle velocity and the local fluid velocity, which, after collision, leads to an unrealistic de-correlation of the real particle velocity and the fluid velocity as seen by the particle. This de-correlation, in turn, causes a spurious decrease of the particle kinetic energy, even though the collisions are assumed perfectly elastic. In this paper, we propose a new model in which the generated fictitious particle velocity is correctly correlated to both the real particle velocity and the local fluid velocity at the particle, hence preventing the spurious loss of the total particle kinetic energy. The model is suitable for small inertial particles. Two algorithms for integrating the collision frequency are also compared to each other. The models are validated using large eddy simulation (LES) of mono-dispersed particle-laden stationary homogeneous isotropic turbulence. Simulations are conducted with spherical particles with different turbulent Stokes number, $$St_t = [0.75 - 5.8]$$ S t t = [ 0.75 - 5.8 ] , and volume fractions, $$\alpha _p = [0.014 - 0.044]$$ α p = [ 0.014 - 0.044 ] , and are compared to the results of the LES using a deterministic discrete particle simulation model.
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Jinasena, Asanthi, and Roshan Sharma. "Estimation of Mud Losses during the Removal of Drill Cuttings in Oil Drilling." SPE Journal 25, no. 05 (June 18, 2020): 2162–77. http://dx.doi.org/10.2118/201230-pa.
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Summary Quantification of fluid losses at the topside is beneficial for early kick-loss detection and automation of the drilling operation. A model-based estimator is a useful tool for this purpose. The real-time estimation of the amount of fluid losses with the cuttings removal could significantly help in this regard, especially for kick detection and automation. However, to the authors’ knowledge, there is no published literature on such attempts. Therefore, a simple dynamic mathematical model of the complete closed-loop oil-well drilling system is developed in this study for estimation of the fluid losses during the removal of drill cuttings at the topside, as well as for monitoring the flow of return fluid during drilling. Furthermore, this model could provide information about the topside fluid-flow rates and fluid losses to other monitoring systems, such as kick- and loss-detection systems and automation systems. The model is used to estimate both the mud-pit level and the fluid losses during the removal of the drill cuttings through the solids-removal equipment. The model-order reduction of the flowline model using orthogonal collocation allows the model to be used in real-time estimations and/or with control systems. It is simple, easy to implement, and, more importantly, shows the necessary dynamic behavior of both the bottomside and topside of a drilling operation simultaneously. The topside model can be used together with bottomside models of varying complexity to estimate both the bottomhole pressure and the fluid losses through the solids-removal system.
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Tenenev, V. A., M. R. Koroleva, and A. A. Chernova. "Application of the Riemann problem with complex equations of state for modeling three-dimensional flows of real media." Journal of Physics: Conference Series 2119, no. 1 (December 1, 2021): 012055. http://dx.doi.org/10.1088/1742-6596/2119/1/012055.
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Abstract The paper considers the numerical simulation of spatial flows of real media in safety valves on the basis of the problem of an arbitrary discontinuity breakdown with complex equations of state. The solution is constructed by means of the developed numerical method, which is a modification of the classical scheme by S. K. Godunov and includes various complex equations of state of matter. The Van der Waals equations of state were used to model the flow of real gases, and the Mie-Grüneisen equation was used to describe the flow of a real weakly compressible fluid. It is shown that the proposed numerical schemes allow for modeling fluid and gas dynamic processes in real fluids and gases with shock waves and contact discontinuities and can be used both in areas of classical medium behavior and in areas with non-classical behavior.
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SEKIGUCHI, Hisako, Kenichi FUNAZAKI, Hideo TANIGUCHI, and Hiromasa KATO. "8F-19 Experimental and numeric research on fluid behavior in real aneurysm model." Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2010.23 (2011): 261–62. http://dx.doi.org/10.1299/jsmebio.2010.23.261.
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Jašíková, Darina, Petr Švarc, Václav Dvořák, and Václav Kopecký. "Fluid velocity and LIF temperature measurement in a real model of heat exchanger." EPJ Web of Conferences 25 (2012): 02009. http://dx.doi.org/10.1051/epjconf/20122502009.
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Sun, Jin Guang, Xin Nian Yang, Yang Li, and Jun Tao Wang. "Real-Time Flame Simulation Based on Volume Rendering." Applied Mechanics and Materials 130-134 (October 2011): 2643–46. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.2643.
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Computer simulation of the flame is difficult to achieve real-time and realistic problem, proposing a fire simulation method based on fluid model and GPU general computing combining. The method is based on the incompressible flame, low-density, non-sticky and so on. Semi-Lagrange method is using to solve the fluid equations, using volume rendering based on 3D texture to rendering the flame. Then, using the method of energy-spectrum of radiation to control the color of the flame, and using the GPU to accelerate in parallel, balance realistic and real time.
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Zuo, Julian Y., Dan Zhang, Francois Dubost, Chengli Dong, Oliver C. Mullins, Michael O’Keefe, and Soraya S. Betancourt. "Equation-of-State-Based Downhole Fluid Characterization." SPE Journal 16, no. 01 (October 27, 2010): 115–24. http://dx.doi.org/10.2118/114702-pa.
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Summary Downhole fluid analysis (DFA), together with focused-sampling techniques and wireline-formation-tester (WFT) tools, provides real-time measurements of reservoir-fluid properties such as the compositions of four or five hydrocarbon components/groups and gas/oil ratio (GOR). With the introduction of a new generation of DFA tools that analyze fluids at downhole conditions, the accuracy and reliability of the DFA measurements are improved significantly. Furthermore, downhole measurements of live-fluid densities are integrated into the new tools. Direct pressure and temperature measurements of the flowline ensure capture of accurate fluid conditions. To enhance these advanced features further, a new method of downhole fluid characterization based on the equation-of-state (EOS) approach is proposed in this work. The motivation for this work is to develop a new approach to maximize the value of DFA data, perform quality assurance or quality control of DFA data, and establish a fluid model for DFA log predictions along with DFA fluid profiling. The basic inputs from DFA measurements are weight percentages of CO2, C1, C2, C3–C5 and C6+, along with live-fluid density and viscosity. A new method was developed in this work to delump and characterize the DFA measurements of C3–C5 (or C2–C5) and C6+ into full-length compositional data. The full-length compositional data predicted by the new method were compared with the laboratory-measured gas chromatograph data up to C30+ for more than 1,000 fluids, including heavy oil, conventional black oil, volatile oil, rich gas condensate, lean gas condensate, and wet gas. These fluids have a GOR range of 8–140,000 scf/STB and a gravity range from 9 to 50°API. A good agreement was achieved between the delumped and gas-chromatograph compositions. In addition, on the basis of the delumped and characterized full-length compositional data, EOS models were established that can be applied to predict fluid-phase behavior and physical properties by virtue of DFA data as inputs. The EOS predictions were validated and compared with the laboratory-measured pressure/volume/temperature (PVT) properties for more than 1,000 fluids. The GOR, formation-volume factor, density, and viscosity predictions were in good agreement with the laboratory measurements. The established EOS model then was able to predict other PVT properties, and the results were compared with the laboratory measurements in good agreement. Consequently, the established EOS models have laid a solid foundation for DFA log predictions in DFA fluid profiling, which has been integrated successfully with DFA measurements in real time to delineate compositional and asphaltene gradients in oil columns and to determine reservoir connectivity. The latter results are beyond the scope of this work and have been given in separate technical papers.
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Jahn, Wolfram, Frane Sazunic, and Carlos Sing-Long. "Towards real-time fire data synthesis using numerical simulations." Journal of Fire Sciences 39, no. 3 (April 16, 2021): 224–39. http://dx.doi.org/10.1177/0734904121993449.
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Synthesising data from fire scenarios using fire simulations requires iterative running of these simulations. For real-time synthesising, faster-than-real-time simulations are thus necessary. In this article, different model types are assessed according to their complexity to determine the trade-off between the accuracy of the output and the required computing time. A threshold grid size for real-time computational fluid dynamic simulations is identified, and the implications of simplifying existing field fire models by turning off sub-models are assessed. In addition, a temperature correction for two zone models based on the conservation of energy of the hot layer is introduced, to account for spatial variations of temperature in the near field of the fire. The main conclusions are that real-time fire simulations with spatial resolution are possible and that it is not necessary to solve all fine-scale physics to reproduce temperature measurements accurately. There remains, however, a gap in performance between computational fluid dynamic models and zone models that must be explored to achieve faster-than-real-time fire simulations.
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Navarro-Hinojosa, Octavio, and Moisés Alencastre-Miranda. "Simulation of Skeletal Muscles in Real-Time with Parallel Computing in GPU." Applied Sciences 10, no. 6 (March 20, 2020): 2099. http://dx.doi.org/10.3390/app10062099.
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Modeling and simulation of the skeletal muscles are usually solved using the Finite Element method (FEM) which, although accurate, commonly needs a complex mesh and the solution is not processed in real-time. In this work, a meshfree model that simulates skeletal muscles considering their functioning and control based on electrical activity, their structure based on biological tissue, and that computes in real-time, is presented. Meshfree methods were used because they are able to surpass most of the limitations that are present in mesh-based methods. The muscular belly was modelled as a particle-based viscoelastic fluid, which is controlled using the monodomain model and shape matching. The smoothed particle hydrodynamics (SPH) method was used to solve both the fluid dynamics and the electrophysiological model. To analyze the accuracy of the method, a similar model was implemented with FEM. Both FEM and SPH methods provide similar solutions of the models in terms of pressure and displacement, with an error of around 0.09, with up to a 10% difference between them. Through the use of General-purpose computing on graphics processing units (GPGPU), real-time simulations that offer a viable alternative to mesh-based models for interactive biological tissue simulations was achieved.
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Manzhai, V. N., A. A. Milke, and D. A. Zubarev. "Calculation of the rate of bulk fluid flow by exponential and logarithmic expressions." Oil and Gas Studies, no. 4 (September 4, 2020): 77–87. http://dx.doi.org/10.31660/0445-0108-2020-4-77-87.
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A formula is presented to calculate the rate of bulk fluid flow in accord with hydrodynamic flow parameters and physical-chemical characteristics of pumping fluids. The formula was derived based on a model knowledge of fluid flow as a continuous sequence of strains — rotations of fluid fragments by the action of shear stress. Laboratory testing of volumetric flow rate depending on the hydrodynamic flow parameters and physical-chemical properties of liquids performed on a turbulent rheometer and as working fluids used ethanol and gasoline. The power and logarithmic dependences of the volume velocity were also checked using real data from the operation of oilfield pipelines. The results obtained satisfactory agree with the calculated data.
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Mehmood, Faisal, Michael Z. Hou, Jianxing Liao, Muhammad Haris, Cheng Cao, and Jiashun Luo. "Multiphase Multicomponent Numerical Modeling for Hydraulic Fracturing with N-Heptane for Efficient Stimulation in a Tight Gas Reservoir of Germany." Energies 14, no. 11 (May 26, 2021): 3111. http://dx.doi.org/10.3390/en14113111.
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Conventionally, high-pressure water-based fluids have been injected for hydraulic stimulation of unconventional petroleum resources such as tight gas reservoirs. Apart from improving productivity, water-based frac-fluids have caused environmental and technical issues. As a result, much of the interest has shifted towards alternative frac-fluids. In this regard, n-heptane, as an alternative frac-fluid, is proposed. It necessitates the development of a multi-phase and multi-component (MM) numerical simulator for hydraulic fracturing. Therefore fracture, MM fluid flow, and proppant transport models are implemented in a thermo-hydro-mechanical (THM) coupled FLAC3D-TMVOCMP framework. After verification, the model is applied to a real field case study for optimization of wellbore x in a tight gas reservoir using n-heptane as the frac-fluid. Sensitivity analysis is carried out to investigate the effect of important parameters, such as fluid viscosity, injection rate, reservoir permeability etc., on fracture geometry with the proposed fluid. The quicker fracture closure and flowback of n-heptane compared to water-based fluid is advantageous for better proppant placement, especially in the upper half of the fracture and the early start of natural gas production in tight reservoirs. Finally, fracture designs with a minimum dimensionless conductivity of 30 are proposed.
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Cai, Lin, and Miao He. "A Numerical Study on the Supersonic Steam Ejector Use in Steam Turbine System." Mathematical Problems in Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/651483.
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Supersonic steam ejector is widely used in steam energy systems such as refrigeration, wood drying equipment, papermaking machine, and steam turbine. In this paper the Computational Fluids Dynamics (CFD) method was employed to simulate a supersonic steam ejector, SST k-w turbulence model was adopted, and both real gas model and ideal gas model for fluid property were considered and compared. The mixing chamber angle, throat length, and nozzle exit position (NXP) primary pressure and temperature effects on entrainment ratio were investigated. The results show that performance of the ejector is underestimated using ideal gas model, and the entrainment ratio is 20%–40% lower than that when using real gas model. There is an optimum mixing chamber angel and NXP makes the entrainment ratio achieve its maximum; as throat length is decreased within a range, the entrainment ratio remains unchanged. Primary fluid pressure has a critical value, and the entrainment ratio reaches its peak at working critical pressure; when working steam superheat degree increases, the entrainment ratio is increased.
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MARTIN, JAMES E., and JUDY ODINEK. "LIGHT SCATTERING STUDIES OF AN ELECTRORHEOLOGICAL FLUID IN OSCILLATORY SHEAR." International Journal of Modern Physics B 10, no. 23n24 (October 30, 1996): 3257–66. http://dx.doi.org/10.1142/s0217979296001707.
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We have conducted a real time, two-dimensional light scattering study of the nonlinear dynamics of field-induced structures in an electrorheological fluid subjected to oscillatory shear. We have developed a kinetic chain model of the observed dynamics by considering the response of a fragmenting/aggregating particle chain to the prevailing hydrodynamic and electrostatic forces. This structural theory is then used to describe the nonlinear rheology of ER fluids.
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Grana, Dario. "Bayesian rock-physics inversion with Kumaraswamy prior models." GEOPHYSICS 87, no. 3 (April 11, 2022): M87—M97. http://dx.doi.org/10.1190/geo2021-0469.1.
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The prediction of rock and fluid volumetric fractions from elastic attributes often is referred to as petrophysical or rock-physics inversion because it requires rock-physics models to map petrophysical properties into geophysical variables, such as velocities and density. Bayesian approaches are suitable for rock-physics inverse problems because the solution, expressed in the form of a probability distribution, can represent the uncertainty of the model predictions due to the errors in the measured data. Bayesian inverse methods often rely on Gaussian prior distributions for their analytical tractability. However, Gaussian distributions are theoretically not applicable to rock and fluid volumetric fractions because, by definition, they are nonzero on the entire set of real numbers, whereas rock and fluid volumetric fractions are bounded between zero and one. The proposed rock physics inversion is based on a Bayesian approach that assumes Kumaraswamy probability density functions for the prior distribution to model double-bounded nonsymmetric continuous random variables between zero and one. The results of the Bayesian inverse problem are the pointwise probability distributions of the rock and fluid volumetric fractions conditioned on the seismic attributes. In the first application, the method is validated using synthetic well-log data for the soft sand and stiff rock-physics models with comparisons with several prior models. In the second application, the method is applied to a 2D real data set to obtain the posterior distribution, the maximum a posteriori, and the confidence intervals of porosity, mineral volumes, and fluid saturations. The most likely model of rock and fluid properties estimated from the posterior distribution assuming a Kumaraswamy prior model finds higher accuracies compared to the corresponding results obtained with a Gaussian prior model.
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Kiuchi, T., H. Izumi, and T. Huke. "An Operation Support System of Large City Gas Networks Based on Fluid Transient Model." Journal of Energy Resources Technology 117, no. 4 (December 1, 1995): 324–28. http://dx.doi.org/10.1115/1.2835430.
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This paper describes the essential features and experience of applying a fluid transient model to the operation support system of large city gas pipeline networks. The system, operating in the second largest city, Osaka, in Japan since 1992, includes the functions of a real-time leak detection and localization, a fast predictive computation of the pressure and flow distributions in networks, and an interactive training simulator using a transient model connected with SCADA training system. To achieve fast forecasting calculation in real-time manner, the combined method of a fully implicit transient calculation for high pressure transmission networks and a steady-state calculation for middle pressure distribution networks is developed. The actual performance of real-time leak detection and the accuracy of the forecasting model are discussed.
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Rimstad, Kjartan, and Henning Omre. "Impact of rock-physics depth trends and Markov random fields on hierarchical Bayesian lithology/fluid prediction." GEOPHYSICS 75, no. 4 (July 2010): R93—R108. http://dx.doi.org/10.1190/1.3463475.
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Early assessments of petroleum reservoirs are usually based on seismic data and observations in a small number of wells. Decision-making concerning the reservoir will be improved if these data can be integrated and converted into a lithology/fluid map of the reservoir. We analyze lithology/fluid prediction in a Bayesian setting, based on prestack seismic data and well observations. The likelihood model contains a convolved linearized Zoeppritz relation and rock-physics models with depth trends caused by compaction and cementation. Well observations are assumed to be exact. The likelihood model contains several global parameters such as depth trend, wavelets, and error parameters; the inference of these is an integral part of the study. The prior model is based on a profile Markov random field parameterized to capture different continuity directions for lithologies and fluids. The posterior model captures prediction and model-parameter uncertainty and is assessed by Markov-chain Monte Carlo simulation-based inference. The inversion model is evaluated on a synthetic and a real data case. It is concluded that geologically plausible lithology/fluid predictions can be made. Rock physics depth trends have influence when cementation is present and/or predictions at depth outside the well range are made. Inclusion of model-parameter uncertainty makes the prediction uncertainties more realistic.
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BATISTA, A. B., J. C. FABRIS, S. V. B. GONCALVES, and J. TOSSA. "QUANTUM PERFECT FLUID COSMOLOGICAL MODEL AND ITS CLASSICAL ANALOGUE." International Journal of Modern Physics A 17, no. 20 (August 10, 2002): 2749. http://dx.doi.org/10.1142/s0217751x0201176x.
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The quantization of gravity coupled to a perfect fluid model leads to a Schrödinger-like equation, where the matter variable plays the role of time. The wave function can be determined, in the flat case, for an arbitrary barotropic equation of state p = α ρ; solutions can also be found for the radiative non-flat case. The wave packets are constructed, from which the expectation value for the scale factor is determined. The quantum scenarios reveal a bouncing Universe, free from singularity. Such quantum cosmological perfect fluid models admit a universal classical analogue, represented by the addition, to the ordinary classical model, of a repulsive stiff matter fluid1,2. The existence of this universal classical analogue may imply that this perfect fluid coupled to gravity model is not a real quantum system. The quantum cosmological perfect fluid model is, for a flat spatial section, formally equivalent to a free particle in ordinary quantum mechanics, for any value of α, while the radiative non-flat case is equivalent to the harmonic oscillator. The repulsive fluid needed to reproduce the quantum results is the same in both cases.
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Cai, Bo, Yun Hong Ding, Yong Jun Lu, Chun Ming He, and Gui Fu Duan. "Leak-Off Coefficient Analysis in Stimulation Treatment Design." Advanced Materials Research 933 (May 2014): 202–5. http://dx.doi.org/10.4028/www.scientific.net/amr.933.202.
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Hydraulic fracturing was first used in the late 1940s and has become a common technique to enhance the production of low-permeability formations.Hydraulic fracturing treatments were pumped into permeable formations with permeable fluids. This means that as the fracturing fluid was being pumped into the formation, a certain proportion of this fluid will being lost into formation as fluid leak-off. Therefore, leak-off coefficient is the most leading parameters of fracturing fluids. The accurate understanding of leak-off coefficient of fracturing fluid is an important guidance to hydraulic fracturing industry design. In this paper, a new field method of leak-off coefficient real time analysis model was presented based on instantaneous shut-in pressure (ISIP). More than 100 wells were fractured using this method in oil field. The results show that average liquid rates of post-fracturing was 22m3/d which double improvement compared with the past treatment wells. It had an important role for hydraulic fracturing stimulation treatment design in low permeability reservoirs and was proven that the new model for hydraulic fracturing treatment is greatly improved.
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Amal Bahnasy and A. M. Abdel-Wahab. "Mathematical Model Represents the Effect of Flexible Endoscopy on Suspension Fluid Flow." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 89, no. 1 (December 5, 2021): 42–61. http://dx.doi.org/10.37934/arfmts.89.1.4261.
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In this manuscript, peristaltic transport induced by a sinusoidal traveling wave in the case for a viscous incompressible Newtonian fluid mixed with rigid spherical particles in the presence of a flexible inner tube, where the inner tube is also moving with a sinusoidal traveling wave of moderate amplitude is studied. The governing equations of the mixture (fluid-particle suspension) are written in two-dimensional cylindrical coordinates. The long-wavelength approximation is used to simplify the system of equations (d<<1). The velocities distribution for both fluid and particles are obtained and evaluated numerically with discussion for special cases. The flow rate, pressure drop, friction forces and shear stress at the outer and inner walls of tubes are derived and represented graphically. In the urinary system, peristalsis is due to involuntary muscular contractions of the ureter wall which drives urine from the kidneys to the bladder through the ureters. A mathematical analysis of peristaltic flow with application to the ureter in presence of flexible endoscopy (Peristaltic Endoscope) is taken as a real application in this study. Finally, conclusions of the research and recommendations for future work are discussed. The results obtained may be relevant to the transport of other physiological fluids and industrial applications in which peristaltic pumping is used.
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Venczel, Márk, Gabriella Bognár, and Árpád Veress. "Temperature-Dependent Viscosity Model for Silicone Oil and Its Application in Viscous Dampers." Processes 9, no. 2 (February 11, 2021): 331. http://dx.doi.org/10.3390/pr9020331.
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Silicone fluids belong to the group of pseudoplastic non-Newtonian fluids with complex rheological characteristics. They are considered in basic and applied researches and in a wide range of industrial applications due to their favorable physical and thermal properties. One of their specific field of applications in the automotive industry is the working fluid of viscous torsional vibration dampers. For numerical studies in the design and development phase of this damping product, it is essential to have thorough rheological knowledge and mathematical description about the silicone oil viscosity. In the present work, adopted rheological measurement results conducted on polydimethylsiloxane manufactured by Wacker Chemie with initial viscosity of 1000 Pas (AK 1 000 000 STAB silicone oil) are processed. As a result of the parameter identification by nonlinear regression, the temperature-dependent parameter curves of the Carreau–Yasuda non-Newtonian viscosity model are generated. By implementing these parameter sets into a Computational Fluid Dynamics (CFD) software, a temperature- and shear-rate-dependent viscosity model of silicone fluid was tested, using transient flow and thermal simulations on elementary tube geometries in the size range of a real viscous torsional vibration damper’s flow channels and filling chambers. The numerical results of the finite volume method provide information about the developed flow processes, with especial care for the resulted flow pattern, shear rate, viscosity and timing.
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Boncinelli, Paolo, Filippo Rubechini, Andrea Arnone, Massimiliano Cecconi, and Carlo Cortese. "Real Gas Effects in Turbomachinery Flows: A Computational Fluid Dynamics Model for Fast Computations." Journal of Turbomachinery 126, no. 2 (April 1, 2004): 268–76. http://dx.doi.org/10.1115/1.1738121.
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A numerical model was included in a three-dimensional viscous solver to account for real gas effects in the compressible Reynolds averaged Navier-Stokes (RANS) equations. The behavior of real gases is reproduced by using gas property tables. The method consists of a local fitting of gas data to provide the thermodynamic property required by the solver in each solution step. This approach presents several characteristics which make it attractive as a design tool for industrial applications. First of all, the implementation of the method in the solver is simple and straightforward, since it does not require relevant changes in the solver structure. Moreover, it is based on a low-computational-cost algorithm, which prevents a considerable increase in the overall computational time. Finally, the approach is completely general, since it allows one to handle any type of gas, gas mixture or steam over a wide operative range. In this work a detailed description of the model is provided. In addition, some examples are presented in which the model is applied to the thermo-fluid-dynamic analysis of industrial turbomachines.
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Lotfi, Amal, and Johann Fischer. "Chemical potentials of model and real dense fluid mixtures from perturbation theory and simulations." Molecular Physics 66, no. 1 (January 1989): 199–219. http://dx.doi.org/10.1080/00268978900100101.
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Qin, Pei Yu, Li Guo, and Zhi Li Hu. "Physically Based Animation of Fluid Movement in a Periodic Domain." Applied Mechanics and Materials 373-375 (August 2013): 395–99. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.395.
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A physically based approach for simulating fluid movement is proposed. Realistic animation and real time simulation are two objectives. Traditional animation technique can obtain virtual movement, but it has difficulty for realistic movement. Compared with the traditional animation technique, physically based animation can represent realistic movement better. The incompressible Navier-Stokes equations are used in our model, and the operator splitting method including semi-Lagrangian scheme and fast Fourier transform is employed to split the model into external force term, advection term, diffusion term and projection term. Every step is stable , so the whole process is also stable. Thus, the big time step can be taken to ensure real time simulation. Compared with the traditional technique, this method can be taken for realistic animation and real time simulation of fluid movement in computer graphics applications.
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Spedding, G. R. "Comparing fluid mechanics models with experimental data." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1437 (August 12, 2003): 1567–76. http://dx.doi.org/10.1098/rstb.2003.1352.
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The art of modelling the physical world lies in the appropriate simplification and abstraction of the complete problem. In fluid mechanics, the Navier–Stokes equations provide a model that is valid under most circumstances germane to animal locomotion, but the complexity of solutions provides strong incentive for the development of further, more simplified practical models. When the flow organizes itself so that all shearing motions are collected into localized patches, then various mathematical vortex models have been very successful in predicting and furthering the physical understanding of many flows, particularly in aerodynamics. Experimental models have the significant added convenience that the fluid mechanics can be generated by a real fluid, not a model, provided the appropriate dimensionless groups have similar values. Then, analogous problems can be encountered in making intelligible but independent descriptions of the experimental results. Finally, model predictions and experimental results may be compared if, and only if, numerical estimates of the likely variations in the tested quantities are provided. Examples from recent experimental measurements of wakes behind a fixed wing and behind a bird in free flight are used to illustrate these principles.
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Demin, A. V., E. N. Sechak, and S. P. Prisyazhnyuk. "Determining the composition of an object based on its hyperspectral image." Computer Optics 45, no. 3 (June 2021): 394–98. http://dx.doi.org/10.18287/2412-6179-co-697.
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The article presents results of the development and research of a hyperspectral imaging spectrometer for analyzing borehole fluids in real operating conditions in the spectral range from 0.35 microns to 2.1 microns. A mathematical model and an algorithm for identifying the borehole fluid by composition and percentage content based on the results of hyperspectral image analysis are developed.
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Gupta, Nikita, Nishant Bhardwaj, Gulam Muhammad Khan, and Vivek Dave. "Global Trends of Computational Fluid Dynamics to Resolve Real World Problems in the Contemporary Era." Current Biochemical Engineering 6, no. 3 (December 28, 2020): 136–55. http://dx.doi.org/10.2174/2212711906999200601121232.
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Background: Computational fluid dynamics (CFD) came into existence with great success, thereby replacing the traditional methods used to simulate the problems related to the flow of fluid. First CFD utilitarian was introduced to the world in 1957, which was developed by a team at Los Alamos National Lab. For tremendous performance and to meet the expected results with ease for modern process conditions, engineers are now more inclined towards the use of simulation software rather than traditional methods. Hence, in the current scenario with the advancement of computer technologies, “CFD is recognized as an excellent tool for engineers to resolve real-world problems.” Introduction: CFD is defined as a branch of fluid dynamics which involves the use of numerical analysis and data structure to solve complications related to the flow of fluids (gasses or liquids). CFD is based on three major principles that are mass conservation, Newton's second law, and energy conservation. CFD has extended to a number of applications at an alarming rate in every field such as in aerospace, sports, food industry, engineering, hydraulics, HVAC (Heating, Ventilating, and Air conditioning), automotive, environmental, power generation, biomedical, pharmaceutical, and many more. Hence, a number of software like ANSYS, Open Foam, SimScale, Gerris, Auto desk simulation, Code_Saturne, etc, are beneficial in order to execute the operations, and to find the solution of realworld problems within a fraction of seconds. Methods: CFD analysis involves three major steps; pre-processing, solution, and post-processing. Preprocessing deals with defining model goals, identification of domain, designing, and creating the grid. Solution involves setting up the numerical model, computing, and monitoring the solution; whereas, post-processing includes results of the examination and revision of the model. Results: The review includes current challenges about the computational fluid dynamics. It is relevant in different areas of engineering to find answers for the problems occurring globally with the aid of a number of simulation-based software hereby, making the world free from complex problems in order to have a non-complicated scenario. Conclusion: Computational fluid dynamics are relevant in each, and every kind of problem related to the fluid flow, either existing in the human body or anywhere. In the contemporary era, there are enormous numbers of simulation-based software, which provide excellent results with just one click, thereby resolving the problems within microseconds. Hence, we cannot imagine our present and upcoming future without CFD, which has ultimately made the execution of work easier, leaving behind non-complicating scenarios. Lastly, we can conclude that “CFD is a faster, smarter, and lighter way in designing process.”
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Rothman, Daniel H. "Cellular‐automaton fluids: A model for flow in porous media." GEOPHYSICS 53, no. 4 (April 1988): 509–18. http://dx.doi.org/10.1190/1.1442482.
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Numerical models of fluid flow through porous media can be developed from either microscopic or macroscopic properties. The large‐scale viewpoint is perhaps the most prevalent. Darcy’s law relates the chief macroscopic parameters of interest—flow rate, permeability, viscosity, and pressure gradient—and may be invoked to solve for any of these parameters when the others are known. In practical situations, however, this solution may not be possible. Attention is then typically focused on the estimation of permeability, and numerous numerical methods based on knowledge of the microscopic pore‐space geometry have been proposed. Because the intrinsic inhomogeneity of porous media makes the application of proper boundary conditions difficult, microscopic flow calculations have typically been achieved with idealized arrays of geometrically simple pores, throats, and cracks. I propose here an attractive alternative which can freely and accurately model fluid flow in grossly irregular geometries. This new method solves the Navier‐Stokes equations numerically using the cellular‐automaton fluid model introduced by Frisch, Hasslacher, and Pomeau. The cellular‐ automaton fluid is extraordinarily simple—particles of unit mass traveling with unit velocity reside on a triangular lattice and obey elementary collision rules—but is capable of modeling much of the rich complexity of real fluid flow. Cellular‐automaton fluids are applicable to the study of porous media. In particular, numerical methods can be used to apply the appropriate boundary conditions, create a pressure gradient, and measure the permeability. Scale of the cellular‐automaton lattice is an important issue; the linear dimension of a void region must be approximately twice the mean free path of a lattice gas particle. Finally, an example of flow in a 2-D porous medium demonstrates not only the numerical solution of the Navier‐Stokes equations in a highly irregular geometry, but also numerical estimation of permeability and a verification of Darcy’s law.