Journal articles: 'Meandering rivers Computer simulation'

1

Sun, Tao, Paul Meakin, and Torstein Jøssang. "A computer model for meandering rivers with multiple bed load sediment sizes: 2. Computer simulations." Water Resources Research 37, no. 8 (August 2001): 2243–58. http://dx.doi.org/10.1029/2000wr900397.

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Zhang, Min, and Rui Xun Lai. "The Water Transferred of Meandering River in Cellular Model." Advanced Materials Research 452-453 (January 2012): 842–45. http://dx.doi.org/10.4028/www.scientific.net/amr.452-453.842.

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We have known that many of the main features of river can be captured in a relatively simple cellular computer model. Here we examine some of the detailed characteristics of this model. We show a new tangential angle and special treatment method in curvature channel in a simple cellular model. The water distribute will be determined by the tangential angle which represent the flow direction. And the same tangential angle cellular in curvature reach will be transport in one group in filially. The results show it can make the flow routing conformed to the real river, and solve the question of curve bending coefficient is too large. The results of the routing scheme are compared with field measurements of cross-section, with the predictions of a more close to the real. It’s indicate that the curvature flow routing scheme outlined here is able to overcome some of the limitations of previous simple cellular automata models and may be suitable for use in curvature reach of river modeling water and sediment transport and channel change in complex fluvial environments. As such this research represents a small and ongoing contribution to the field of numerical simulation of curvature channel processes.

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Sun, Tao, Paul Meakin, Torstein Jøssang, and Klaus Schwarz. "A Simulation Model for Meandering Rivers." Water Resources Research 32, no. 9 (April 1996): 2937–54. http://dx.doi.org/10.1029/96wr00998.

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Ma, K., and W. L. Wei. "Simulation of Flow in a Rectangular Meandering Channel." Applied Mechanics and Materials 130-134 (October 2011): 2688–91. http://dx.doi.org/10.4028/www.scientific.net/amm.130-134.2688.

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This paper is concerned with the numerical solution of two-dimensional flows in a rectangular meandering channel. The technique of boundary-fitted coordinate system is used to overcome the difficulties resulting from the complicated shape of natural river boundaries; the method of physical fractional steps is used to solve the partial differential equations in the transformed plane. Comparison between computed and experimental data shows a satisfactory agreement.

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Viseur, Sophie. "Turbidite reservoir characterization : object-based stochastic simulation meandering channels." Bulletin de la Société Géologique de France 175, no. 1 (January 1, 2004): 11–20. http://dx.doi.org/10.2113/175.1.11.

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Abstract Stochastic imaging has become an important tool for risk assessment and has successfully been applied to oil field management. This procedure aims at generating several possible and equiprobable 3D models of subsurface structures that enhance the available data set. Among these stochastic simulation techniques, object-based approaches consist of defining and distributing objects reproducing underground geobodies. A technical challenge still remains in object-based simulation. Due to advances in deep water drilling technology, new hydrocarbon exploration has been opened along the Atlantic margins. In these turbidite oil fields, segments of meandering channels can be observed on high-resolution seismic horizons. However, no present object-based simulation technique can reproduce exactly such known segments of channel. An improved object-based approach is proposed to simulate meandering turbidite channels conditioned on well observations and such seismic data. The only approaches dealing with meandering channels are process-based as opposed to structure-imitating. They are based on the reproduction of continental river evolution through time. Unfortunately, such process-based approaches cannot be used for stochastic imaging as they are based on equations reflecting meandering river processes and not turbiditic phenomena. Moreover, they incoporate neither shape constraints (such as channel dimensions and sinuosity) nor location constraints, such as well data. Last, these methods generally require hydraulic parameters that are not available from oil field study. The proposed approach aims at stochastically generating meandering channels with specified geometry that can be constrained to pass through well-observations. The method relies on the definition of geometrical parameters that characterize the shape of the expected channels such as dimensions, directions and sinuosity. The meandering channel object is modelled via a flexible parametric shape. The object is defined by a polygonal center-line (called backbone) that supports several sections. Channel sinuosity and local channel profiles are controlled by the backbone and, respectively the sections. Channel generation is performed within a 2D domain, D representing the channel-belt area. The proposed approach proceeds in two main steps. The first step consists in generating a channel center-line (C) defined by an equation v=Z(u) within the domain D. The geometry of this line is simulated using a geostatistical simulation technique that allows the generation of controlled but irregular center-lines conditioned on data points. During the second step, a vector field enabling the curve (C) to be transformed into a meandering curve (C’) is estimated. This vector field acts as a transform that specifies the third degree of channel sinuosity, in other words, the meandering parts of the loops. This field is parameterized by geometrical parameters such as curvature and tangent vectors along the curve (C) and the a priori maximum amplitude of the meander loops of the curve (C’). To make channel objects pass through conditioning points, adjustment vectors are computed at these locations and are interpolated along the curves. Synthetic datasets have been built to check if a priori parameters such as tortuosity are reproduced, and if the simulations are equiprobable. From this dataset, hundred simulations have been generated and enable one to verify that these two conditions are satisfied. Equiprobability is however not always satisfied from data points that are very close and located in a multivalued part of a meander : preferential orientation of the loops may indeed be observed. Solving this issue will be the focus of future works. Nevertheless, the results presented in this paper show that the approach provides satisfying simulations in any other configurations. This approach is moreover well-suited for petroleum reservoir characterization because it only needs specification of geometrical parameters such as dimension and sinuosity that can be inferred from the channel parts seen on seismic horizons or analogues.

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Meakin, Paul, Tao Sun, Torstein Jøssang, and Klaus Schwarz. "A simulation model for meandering rivers and their associated sedimentary environments." Physica A: Statistical Mechanics and its Applications 233, no. 3-4 (December 1996): 606–18. http://dx.doi.org/10.1016/s0378-4371(96)00197-5.

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Darby, Stephen E., Andrei M. Alabyan, and Marco J. Van de Wiel. "Numerical simulation of bank erosion and channel migration in meandering rivers." Water Resources Research 38, no. 9 (September 2002): 2–1. http://dx.doi.org/10.1029/2001wr000602.

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Yan, Xue, Jinliang Zhang, Yang Li, Yan Zhang, and Long Sun. "Reconstruction of Planforms and Architecture of the Meandering Paleo-Channels—A Case Study of the 1st Member of Shanxi Formation, Central of Sulige Gas Field, Ordos Basin." Water 14, no. 3 (February 5, 2022): 477. http://dx.doi.org/10.3390/w14030477.

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Although a large number of meandering rivers have been studied by means of modern sedimentation, instrument detection, numerical simulation, flume experiment and field outcrop, and a lot of achievements have been made, there are not many fine anatomical examples of deep buried ancient rivers, which is a situation that still needs to be improved. The main difficulties in the research of deep, ancient meandering rivers are the acquisition of data and the incompleteness of structure, which are both difficulties and challenges. Under the guidance of the modern meandering river fan sedimentary model and migration law, we established the scheme of meandering river geomorphology and structure. In the process of river migration, a variety of single migration models (expansion, contraction, rotation, and translation) and composite migration models can be distinguished. By analyzing the distribution structure characteristics of channel configuration elements in different migration modes, the coupled model of the meandering channel plane and profile structure is established by systematically constructing plane and profile combined with a three-dimensional channel configuration model. Based on the data of the dense well, taking the Shan 11 sublayer in the Su-x block of the Sulige gas field as an example, the reservoir structure of the deep, ancient meandering channel is dissected. In order to reconstruct the evolution of the deep, ancient channel and make it more consistent with the real laws of river migration and evolution, the morphological migration law of the modern river is applied to the ancient sedimentation, and the migration configuration is dissected by combining with the plane-profile structure coupled model. It further reveals the heterogeneity, the vertical distribution and the superposition form of the channel sand, and enriches the theory of the reservoir configuration of underground fluvial facies, all of which are significant for oil and gas exploration and development.

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Wang, Pingyi, Jian Li, Meili Wang, Jielong Hu, and Fan Zhang. "Numerical Simulation of the Hydraulic Characteristics and Fish Habitat of a Natural Continuous Meandering River." Sustainability 14, no. 16 (August 9, 2022): 9798. http://dx.doi.org/10.3390/su14169798.

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Increasing international attention is being focused on the construction of ecological waterways. Ecological waterways are not only able to successfully sustain the navigational functions for ships, but also provide a stable long-term environment in which fish can survive. In nature, meandering rivers are the most common form. Compared with straight rivers, their flow conditions are complex and not conducive to ship navigation and fish survival. There has been less research conducted on the construction of ecological waterways in naturally curving rivers. Therefore, in this paper, a naturally continuous curved river was used as a research object, and numerical simulation was employed to study the hydraulic characteristics of the river and the survival environment by fish by introducing the Shannon diversity index. It was concluded that a naturally continuous curved river cannot meet the navigational requirements and does not provide a stable survival environment for fish. After proposing a targeted channel restoration plan, the hydraulic characteristics of the flow were significantly improved, and the flow velocity Shannon diversity index was reduced. The restored channel met the navigational requirements of vessels, and provided a more stable environment for fish. In the construction of the continuous bend river ecological corridor, the location of the continuous bend stream connection was used as a key restoration area. This paper provides ideas and basic research for the sustainable development of ecological river channels and the construction of continuous curved river channels.

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Yang, Xiaolei, and Fotis Sotiropoulos. "A Review on the Meandering of Wind Turbine Wakes." Energies 12, no. 24 (December 11, 2019): 4725. http://dx.doi.org/10.3390/en12244725.

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Meandering describes the large-scale, low frequency motions of wind turbine wakes, which could determine wake recovery rates, impact the loads exerted on turbine structures, and play a critical role in the design and optimal control of wind farms. This paper presents a comprehensive review of previous work related to wake meandering. Emphasis is placed on the origin and characteristics of wake meandering and computational models, including both the dynamic wake meandering models and large-eddy simulation approaches. Future research directions in the field are also discussed.

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Akihiko, Nakayama, Huan Tao Goh, and Seak Ni Chai. "Effects of Riparian Vegetation on the Transport and Accumulation of Floating Objects in a Meandering River." E3S Web of Conferences 65 (2018): 07003. http://dx.doi.org/10.1051/e3sconf/20186507003.

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In order to study and understand the characteristics of transport and depositions of floating objects in real rivers, Large Eddy Simulation (LES) method of real river flows with complex bathymetry, the riparian vegetation and the floating objects has been developed and applied to a meandering river in Perak, Malaysia. The movement and accumulation of floating objects are different for different sizes and the shapes of the objects. The vegetation that may exists on the bed and the banks also are seen to influence the positions where the objects are accumulated and deposited. The results can be used to control the increasing amount of solid objects washed into the rivers and to the ocean.

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Khosronejad, Ali, Jessica L. Kozarek, Margaret L. Palmsten, and Fotis Sotiropoulos. "Numerical simulation of large dunes in meandering streams and rivers with in-stream rock structures." Advances in Water Resources 81 (July 2015): 45–61. http://dx.doi.org/10.1016/j.advwatres.2014.09.007.

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13

Okamoto, Takashi. "Developmental regulation and morphological saltation in the heteromorph ammonite Nipponites." Paleobiology 14, no. 3 (1988): 272–86. http://dx.doi.org/10.1017/s0094837300012008.

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Nipponites, a Late Cretaceous nostoceratid ammonite, shows a peculiar meandering shell growth in the middle-late stage. Assuming neutral buoyancy, and a constant aperture angle relative to the sea bottom, meandering growth of this ammonite was modeled by computer simulation. In this model, the meandering shell growth is controlled by regulation of life orientation. The remarkable similarity in the coiling modes and rib obliquity patterns between the computer-simulated and actual specimens strongly suggests a free living mode of life in Nipponites with an approximately neutral buoyancy. The simulation also suggests that morphological saltation from a simple helicoid form like Eubostrychoceras japonicum to a meandering shell form like Nipponites occurred abruptly without any intermediate form by minor change of the upper and lower limits of growth direction.

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14

Sun, Tao, Paul Meakin, and Torstein Jøssang. "A computer model for meandering rivers with multiple bed load sediment sizes: 1. Theory." Water Resources Research 37, no. 8 (August 2001): 2227–41. http://dx.doi.org/10.1029/2000wr900396.

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15

Echeverribar, Isabel, Mario Morales-Hernández, Pilar Brufau, and Pilar García-Navarro. "Numerical simulation of 2D real large scale floods on GPU: the Ebro River." E3S Web of Conferences 40 (2018): 06007. http://dx.doi.org/10.1051/e3sconf/20184006007.

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Modern flood risk management and mitigation plans incorporate the presence of numerical models that are able to assess the response of the system and to help in the decision-making processes. The shallow water system of equations (SWE) is widely used to model free surface flow evolution in river flooding. Although 1D models are usually adopted when simulating long rivers due to their computational efficiency, 2D models approximate better the behaviour in floodplains of meandering rivers using a fine mesh which implies unaffordable computations in real-world applications. However, the advances on parallelization methods accelerate computation making 2D models competitive. In particular, GPU technology offers important speed-ups which allow fast simulations of large scale scenarios. In this work, an example of the scope of this technology is presented. Several past flood events have been modelled using GPU. The physical domain (middle part of the Ebro River in Spain) has a extent of 477 km2, which gives rise to a large computational grid. The steps followed to carry out the numerical simulation are detailed, as well as the comparison between numerical results and observed flooded areas reaching coincidences up to 87.25 % and speed enhancements of 1-h of simulation time for 1-day flood event. These results lead to the feasible application of this numerical model in real-time simulation tools with accurate and fast predictions useful for flood management.

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Yapa, Poojitha D., Hung Tao Shen, Steven F. Daly, and Stephen C. Hung. "Oil Spill Simulation in Rivers." International Oil Spill Conference Proceedings 1991, no. 1 (March 1, 1991): 593–600. http://dx.doi.org/10.7901/2169-3358-1991-1-593.

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ABSTRACT Computer models recently have been developed for simulating oil slick transport in rivers, including the connecting channels of the Great Lakes, the upper St. Lawrence River, and the Allegheny-Monongahela-Ohio River system. In these models, a Lagrangian discrete-parcel algorithm is used to determine the location and concentration distribution of the oil in the river as well as the deposition of oil on the shore. The model for the Great Lakes connecting channels (ROSS) is a two-dimensional surface slick model which considers advection, spreading, horizontal diffusion, evaporation, dissolution, and shoreline deposition. The model is applicable to both open water and ice covered conditions. Models for the St. Lawrence River and the Ohio River System are developed based on a two-layer scheme (ROSS2) which considers vertical mixing and emulsiflcation processes in addition to the processes considered in the surface slick model. All of these models are implemented on microcomputers and can be used as integral parts of oil spill response programs to assist cleanup actions.

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Ramón, C. L., J. Prats, and F. J. Rueda. "Simulation of Turbulent Flows in River Confluences and Meandering Channels with a Cartesian 3D Free Surface Hydrodynamic Model." International Journal of Computational Methods 12, no. 06 (December 2015): 1550035. http://dx.doi.org/10.1142/s0219876215500358.

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Three-dimensional primitive equations (3DPE) become a reasonable approach in hydrodynamics in terms of computational costs when the length of the computational domain and/or computational time scales increases. However, given the simplified set of equations used in the analysis, results with 3DPE-based models are expected to be approximate and before attempting to reproduce complex natural flows they first need to be validated against more simple flows observed in laboratory settings. Here, the validity of Cartesian free-surface hydrodynamic models to reproduce three turbulent flows characteristic of river environments is tested: (1) the development of shallow mixing layers, (2) flow pass a lateral cavity and (3) flow in open channel with mild curvature. Errors between measured and modeled values were generally less than 10%, proving their validity to reproduce such turbulent flows and their potential for simulations in more complex natural environments, such it is the case of the confluence between the Ebro and Segre rivers into Ribarroja reservoir.

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Shokirov, B., B. Norkulov, Kh Nishanbaev, M. Khurazbaev, and B. Nazarov. "Computer simulation of channel processes." E3S Web of Conferences 97 (2019): 05012. http://dx.doi.org/10.1051/e3sconf/20199705012.

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The article discusses the results of numerical studies of flow movement with a sharp change in the channel parameters. The numerical study of the flow in the channels and rivers creates the possibility of a multivariate forecast of channel processes, rivers, and requires minimal expenditures. The purpose of the study is to determine the main objectives and directions of research in the area under consideration. A mathematical model and a computer program have been developed that allow solving a wide range of tasks for modelling currents in the channels of various difficulties, taking into account daily regulation. This makes it possible to identify and proactively take measures, such as: determining the time to reach the flow along the channel; the establishment of water volume flow in an arbitrary channel; taking emergency measures to regulate the incoming residual volume of water after its termination into the system, in the event of an accident at pumping stations; identification of the nature and direction of channel processes; prevention of undermining of supports and damage to power lines passing through the channel, and many other engineering tasks. The developed tested mathematical model allows in real conditions and in real time to help the operational services of large channels in the operational management of actions, in emergency situations, and the choice of the most effective, at any point in time, measures to minimize the consequences. Analysis of the results of many researchers has created the opportunity for the authors of this article to conclude that the above system of hydrodynamic equations is applicable in mathematical modelling of motion, taking into account the transverse circulation of the flow.

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TAŞAR, Bestami, Fatih ÜNEŞ, and Ercan GEMİCİ. "Laboratory and numerical investigation of the 2-array submerged vanes in meandering open channel." Mathematical Biosciences and Engineering 20, no. 2 (2022): 3261–81. http://dx.doi.org/10.3934/mbe.2023153.

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<abstract>In the case of flooding in rivers, river regulation structures are important since scours occur on the outer meander due to high flow velocities. In this study, 2-array submerged vane structures were investigated which is a new method in the meandering part of open channels, both laboratory and numerically with an open channel flow discharge of 20 L/s. Open channel flow experiments were carried out by using a submerged vane and without a vane. The flow velocity results of the computational fluid dynamics (CFD) models were compared to the experimental results and the results were found compatible. The flow velocities were investigated along with depth using the CFD and found that the maximum velocity was reduced by 22–27% along the depth. In the outer meander, the 2-array submerged vane with a 6-vane structure was found to affect the flow velocity by 26–29% in the region behind the vane.</abstract>

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Jing, Hefang, Chunguang Li, Yakun Guo, and Weilin Xu. "Numerical simulation of turbulent flows in trapezoidal meandering compound open channels." International Journal for Numerical Methods in Fluids 65, no. 9 (February 16, 2011): 1071–83. http://dx.doi.org/10.1002/fld.2229.

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21

Lee, Jiyong, Mirko Musa, Chris Feist, Jinjin Gao, Lian Shen, and and Michele Guala. "Wake Characteristics and Power Performance of a Drag-Driven in-Bank Vertical Axis Hydrokinetic Turbine." Energies 12, no. 19 (September 21, 2019): 3611. http://dx.doi.org/10.3390/en12193611.

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Preliminary design of a new installation concept of a drag-driven vertical axis hydrokinetic turbine is presented. The device consists of a three-bladed, wheel-shaped, turbine partially embedded in relatively shallow channel streambanks. It is envisioned to be installed along the outer banks of meandering rivers, where the flow velocity is increased, to maximize energy extraction. To test its applicability in natural streams, flume experiments were conducted to measure velocity around the turbine and power performance using Acoustic Doppler Velocimetry and a controlled motor drive coupled with a torque transducer. The experiment results comprise the power coefficient, the spatial evolution of the mean velocity deficit, and a description of the flow structures generated by the turbine and responsible for the unsteadiness of the wake flow. Applying a triple decomposition on the Reynolds stresses, we identify the dominant contribution to such unsteadiness to be strongly associated with the blade passing frequency.

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Kim, Jun Song, Donghae Baek, and Inhwan Park. "Evaluating the Impact of Turbulence Closure Models on Solute Transport Simulations in Meandering Open Channels." Applied Sciences 10, no. 8 (April 16, 2020): 2769. http://dx.doi.org/10.3390/app10082769.

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River meanders form complex 3D flow patterns, including secondary flows and flow separation. In particular, the flow separation traps solutes and delays their transport via storage effects associated with recirculating flows. The simulation of the separated flows highly relies in the performance of turbulence models. Thus, these closure schemes can control dispersion behaviors simulated in rivers. This study performs 3D simulations to quantify the impact of the turbulence models on solute transport simulations in channels under different sinuosity conditions. The 3D Reynolds-averaged Navier-Stokes equations coupled with the k − ε , k − ω and SST k − ω models are adopted for flow simulations. The 3D Lagrangian particle-tracking model simulates solute transport. An increase in sinuosity causes strong transverse gradients of mean velocity, thereby driving the onset of the separated flow recirculation along the outer bank. Here, the onset and extent of the flow separation are strongly influenced by the turbulence models. The k − ε model fails to reproduce the flow separation or underestimates its size. As a result, the k − ε model yields residence times shorter than those of other models. In contrast, the SST k − ω model exhibits a strong tailing of breakthrough curves by generating more pronounced flow separation.

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Hodges, Ben R. "Rivers and Electric Networks: Crossing Disciplines in Modeling and Simulation." Foundations and Trends® in Electronic Design Automation 8, no. 1 (2014): 1–116. http://dx.doi.org/10.1561/1000000033.

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24

Li, Junhua, Mingwu Zhang, Enhui Jiang, Li Pan, Aoxue Wang, Yafei Wang, and Shengqi Jian. "Influence of Floodplain Flooding on Channel Siltation Adjustment under the Effect of Vegetation on a Meandering Riverine Beach." Water 13, no. 10 (May 18, 2021): 1402. http://dx.doi.org/10.3390/w13101402.

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Flooding in a sediment-laden floodplain is affected by riverine beach vegetation and the shape of a meandering compound channel. The laws of water and sediment exchange and the deposition distribution in beach troughs are very complex. These factors play a significant role in the formation and development of secondary suspended rivers, in the adjustment of the beach horizontal gradient, and even in the evolution of the flood control situation. In this study, we used a combination of experimental simulation and theoretical research to carry out a generalized model test of floodplain flooding evolution, analyzed the lateral distribution characteristics of sediment-laden flow and sediment factors in a meandering compound channel under the conditions of beach vegetation, and revealed the pros and cons of beach vegetation on the adjustment of the beach and channel siltation. The model test results of the flooding in the floodplain in the compound channel with meandering vegetation showed that the main stream was not only concentrated in the main channel but also appeared near the foot of the left and right bank levees and formed flood discharges along the embankment. As the riverine beach siltation was mainly concentrated at the riverine beach lip, the vegetation on the riverine beach had a significant effect on slowing down the flow velocity. Whether it was a row or full vegetation on both sides of the bank, this played an important role in the stability of the main channel. When there was no vegetation on the riverine beach, the main channel was easy to move. The arrangement of full vegetation on the riverine beach had a uniform effect on the velocity distribution of the riverine beach, which reduced the phenomenon of excessive velocity at the foot of the riverine beach and increased the velocity effect in the main channel. These results will provide a theoretical basis for the utilization of riverine beach areas and river management in the lower Yellow River and have a great significance for enriching the basic theory of water and sediment movement and promoting the integration of hydraulics, river dynamics, and ecology.

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Jing, H., Y. Guo, C. Li, and J. Zhang. "Three-dimensional numerical simulation of compound meandering open channel flow by the Reynolds stress model." International Journal for Numerical Methods in Fluids 59, no. 8 (March 20, 2009): 927–43. http://dx.doi.org/10.1002/fld.1855.

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Zhu, Hai, Shengjie Lu, Lingling Wang, Jieru Xu, and Saiyu Yuan. "Numerical Study of Mixing Process by Point Source Pollution with Different Release Positions in a Sinuous Open Channel." Water 14, no. 12 (June 13, 2022): 1903. http://dx.doi.org/10.3390/w14121903.

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The process of pollutant mixing is significantly influenced by secondary flow and turbulence in meandering rivers. To investigate the influence of different point source release positions on the pollutant mixing process in sinuous open channel flows, a 3D large-eddy simulation (LES) model based on OpenFOAM was established to simulate the process of passive scalar transport in a sinuous channel with a rectangular cross-section. After verification by a flume experiment, two sets of cases in which the point sources were arranged at identical intervals in spanwise and streamwise directions were configured to evaluate the mixing efficiency. The effect of flow structure, secondary motion, and the turbulent viscosity on the scalar transport and mixing was discussed. The distribution of scalar as well as the scalar flux was analyzed in detail, and the fluctuation characteristics were also described. The results demonstrate that due to the existence of secondary flow in the sinuous channel, different transverse and streamwise release positions of the point source have significant influence on mixing efficiency and spatial distribution of the pollutant. The point source placed near the center of the cross-section in transverse or near the apex of the bend in streamwise result in higher mixing efficiency. Mixing efficiency calculated by different indices can be different, which requires comprehensive assessment.

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Giri, S., Y. Shimizu, and B. Surajate. "Laboratory measurement and numerical simulation of flow and turbulence in a meandering-like flume with spurs." Flow Measurement and Instrumentation 15, no. 5-6 (October 2004): 301–9. http://dx.doi.org/10.1016/j.flowmeasinst.2004.05.002.

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Song, Zida, Quan Liu, Zhigen Hu, Chunsheng Zhang, Jinming Ren, Zhexin Wang, and Jianhai Tian. "Construction Diversion Risk Assessment for Hydropower Development on Sediment-Rich Rivers." Energies 13, no. 4 (February 19, 2020): 938. http://dx.doi.org/10.3390/en13040938.

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Hydropower is an important renewable energy, and Construction Diversion Risk (CDR) should be highlighted and assessed during hydropower development. Since sediment-rich rivers are widely existing around the world and have great hydro-energy potential, assessing CDR for hydropower development on sediment-rich rivers in terms of engineering feasibility is of significance. This paper proposes a CDR assessment method for the sediment-rich hydropower development environment. The method is concise and practical, reflects diversion uncertainties and correlation, and mainly adopts the Gumbel–Hougaard Copula and the Monte Carlo Simulation. Through simulating flood evolution and sediment impact during diversion, the method can assess CDR basing on the cofferdam overtopping probability. Case results show that the proposed method can achieve CDR assessment on a sediment-rich river and highlights sediment impact on the diversion risk. Through results discussion, the risk feature of construction diversion on sediment-rich rivers is revealed, that sediment impact causes the dynamic and yearly-risen CDR. Hence, our conclusions are: (1) the proposed method is feasible, effective and has industrial potential, and (2) a diversion scheme on sediment-rich rivers is suggested that adopts the design with high or yearly-heightening cofferdams, based on the advanced CDR assessment to cope with the risk features of sediment-rich diversion environments.

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Sekine, M., M. Ukita, and H. Nakanishi. "Systematic Pollutegraph Simulation for Real Scale River Basin." Water Science and Technology 23, no. 1-3 (January 1, 1991): 141–50. http://dx.doi.org/10.2166/wst.1991.0410.

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This study describes the model for predicting the run-off load of pollutants through rivers into eutrophic lakes and inner sea areas. The model is composed of three stages: discharged load prediction; flow-rate prediction; and run-off load prediction. The discharged load in the river basin is estimated by using a pollutant loading factor method. The flow-rate which is necessary for the formula to predict the run-off load, was obtained by a tank model method. The run-off load prediction process consists of two stages: flow-out stage and flow-down stage. The flow-out stage represents the process in which the discharged load, including that from non-point source, flows out through gutters or small streams into the main river. The flow-down stage represents the process in which the flow-out load flows down through the main river to an observing station. There have been many studies dealing with water quality and load of pollutants in rivers. However, only a few of these studies have analyzed the relationship of human activities in the river basins quantitatively. Using this model, a computer program for pollutegraph simulation was constructed and applied to the river Ibo in Hyougo prefecture, JAPAN. The results obtained showed in accordance with the data obtained from field investigation.

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Lotsari, Eliisa S., Mikel Calle, Gerardo Benito, Antero Kukko, Harri Kaartinen, Juha Hyyppä, Hannu Hyyppä, and Petteri Alho. "Topographical change caused by moderate and small floods in a gravel bed ephemeral river – a depth-averaged morphodynamic simulation approach." Earth Surface Dynamics 6, no. 1 (March 5, 2018): 163–85. http://dx.doi.org/10.5194/esurf-6-163-2018.

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Abstract. In ephemeral rivers, channel morphology represents a snapshot at the end of a succession of geomorphic changes caused by floods. In most cases, the channel shape and bedform migration during different phases of a flood hydrograph cannot be identified from field evidence. This paper analyses the timing of riverbed erosion and deposition of a gravel bed ephemeral river channel (Rambla de la Viuda, Spain) during consecutive and moderate- (March 2013) and low-magnitude (May 2013) discharge events, by applying a morphodynamic model (Delft3D) calibrated with pre- and post-event surveys by RTK-GPS points and mobile laser scanning. The study reach is mainly depositional and all bedload sediment supplied from adjacent upstream areas is trapped in the study segment forming gravel lobes. Therefore, estimates of total bedload sediment mass balance can be obtained from pre- and post-field survey for each flood event. The spatially varying grain size data and transport equations were the most important factors for model calibration, in addition to flow discharge. The channel acted as a braided channel during the lower flows of the two discharge events, but when bars were submerged in the high discharges of May 2013, the high fluid forces followed a meandering river planform. The model results showed that erosion and deposition were in total greater during the long-lasting receding phase than during the rising phase of the flood hydrographs. In the case of the moderate-magnitude discharge event, deposition and erosion peaks were predicted to occur at the beginning of the hydrograph, whereas deposition dominated throughout the event. Conversely, the low-magnitude discharge event only experienced the peak of channel changes after the discharge peak. Thus, both type of discharge events highlight the importance of receding phase for this type of gravel bed ephemeral river channel.

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ShahiriParsa, Ahmad, Mohammad Noori, Mohammad Heydari, and Mahmood Rashidi. "Floodplain Zoning Simulation by Using HEC-RAS and CCHE2D Models in the Sungai Maka River." Air, Soil and Water Research 9 (January 2016): ASWR.S36089. http://dx.doi.org/10.4137/aswr.s36089.

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River flooding causes several human and financial casualties. It is necessary to perform research studies and implement subsequent actions consistent with the nature of the river. In order to reduce flood damage, floodplain zoning maps and river cross-sectional boundaries are important to nonstructural measures in planning and optimizing utilization of the areas around the river. Due to the complex behavior of the rivers during floods, computer modeling is the most efficient tool with the least possible cost to study and simulate the behavior of the rivers. In this study, one-dimensional model Hydrologic Engineering Centers–-River Analysis System and two-dimensional model CCHE2D were used to simulate the flood zoning in the Sungai Maka district in Kelantan state, Malaysia. The results of these two models in most sections approximately match. Most differences in the results were in the shape of the river.

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Alvarez-Vázquez, L. J., A. Martínez, C. Rodríguez, M. E. Vázquez-Méndez, and M. A. Vilar. "Optimal shape design for fishways in rivers." Mathematics and Computers in Simulation 76, no. 1-3 (October 2007): 218–22. http://dx.doi.org/10.1016/j.matcom.2007.01.029.

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Peng, Jiayu, Chunling Jin, Yue Wu, Zeying Hou, Sijia Gao, Zhaosheng Chu, and Binghui Zheng. "Modeling Non-Point Source Nutrient Loads with Different Cropping Systems in an Agricultural Lake Watershed in Southwestern China: From Field to Watershed Scale." Mathematics 10, no. 21 (October 31, 2022): 4047. http://dx.doi.org/10.3390/math10214047.

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Understanding the influence of cropping systems on non-point source pollution (NPSP) is crucial, since NPSP has become the major nutrient source of lake eutrophication. How to identify the characteristics of the N and P balance at different spatial and temporal scales remains a challenge in pollution control and decision-making. In this study, we built a soil and water assessment tool (SWAT) model coupled with an export coefficient model for a NPSP simulation in the North of Erhai Lake Basin (NELB). A method was proposed to study the N and P transport from fields and the individual sub-basins to Erhai Lake using SWAT simulation. The results showed that the N and P loss fields were mainly situated in the vicinity of the Fengyu river and along the mainstream of the Miju and Mici rivers. N and P loss fields were mainly occupied by rice–broad bean/rice–rapeseed crops and vegetables. While the critical N and P load contribution areas were situated in the vicinity of downstream of the Miju, Yong’an, and Luoshi rivers. The effects of different cropping systems on the N and P export to the watershed were insignificant in the NELB and decreased by 4–9% when changing cropping system compared to the original crops. The NPSP discharged from the critical areas was retained and purified by the flow and the reservoirs scattered along the rivers, and it was noticed that the N and P loss was mainly from the critical pollution discharge areas located downstream of Miju river. This study can provide an important simulation method for understanding NPSPs and, therefore, can help authorities improve agricultural land use and reduce lake pollution.

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Nguyen, Van Luc, Tomohiro Degawa, and Tomomi Uchiyama. "Numerical simulation of annular bubble plume by vortex in cell method." International Journal of Numerical Methods for Heat & Fluid Flow 29, no. 3 (March 4, 2019): 1103–31. http://dx.doi.org/10.1108/hff-03-2018-0094.

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PurposeThis study aims to provide discussions of the numerical method and the bubbly flow characteristics of an annular bubble plume.Design/methodology/approachThe bubbles, released from the annulus located at the bottom of the domain, rise owing to buoyant force. These released bubbles have diameters of 0.15–0.25 mm and satisfy the bubble flow rate of 4.1 mm3/s. The evolution of the three-dimensional annular bubble plume is numerically simulated using the semi-Lagrangian–Lagrangian (semi-L–L) approach. The approach is composed of a vortex-in-cell method for the liquid phase and a Lagrangian description of the gas phase.FindingsFirst, a new phenomenon of fluid dynamics was discovered. The bubbly flow enters a transition state with the meandering motion of the bubble plume after the early stable stage. A vortex structure in the form of vortex rings is formed because of the inhomogeneous bubble distribution and the fluid-surface effects. The vortex structure of the flow deforms as three-dimensionality appears in the flow before the flow fully develops. Second, the superior abilities of the semi-L–L approach to analyze the vortex structure of the flow and supply physical details of bubble dynamics were demonstrated in this investigation.Originality/valueThe semi-L–L approach is applied to the simulation of the gas–liquid two-phase flows.

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Werther, Lukas, Tanja Menn, Johannes Schmidt, and Hartmut Müller. "Modelling pre-modern flow distances of inland waterways – a GIS study in southern Germany." Virtual Archaeology Review 12, no. 25 (July 14, 2021): 42. http://dx.doi.org/10.4995/var.2021.15245.

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Rivers form major traffic arteries in pre-modern Central Europe and accurate regional to supra-regional network models of inland navigation are crucial for economic history. However, navigation distances have hitherto been based on modern flow distances, which could be a significant source of error due to modern changes in flow distance and channel pattern. Here, we use a systematic comparison of vectorized old maps, which enlighten the fluvial landscape before most of the large-scale river engineering took place, and modern opensource geodata to deduce change ratios of flow distance and channel patterns. The river courses have been vectorised, edited and divided into comparable grid units. Based on the thalweg, meandering and braided/anabranching river sections have been identified and various ratios have been calculated in order to detect changes in length and channel patterns. Our large-scale analytical approach and Geographic Information System (GIS) workflow are transferable to other rivers in order to deduce change ratios on a European scale. The 19th century flow distance is suitable to model pre-modern navigation distances. As a case study, we have used our approach to reconstruct changes of flow pattern, flow distance and subsequent changes in navigation distance and transportation time for the rivers Altmühl, Danube, Main, Regnitz, Rednitz, Franconian and Swabian Rezat (Southern Germany). The change ratio is rather heterogeneous with length and travel time changes of the main channel up to 24% and an extensive transformation of channel morphology in many river sections. Based on published travel time data, we have modelled the effect of our change ratios. Shipping between the commercial hubs Ulm and Regensburg, to give an example, was up to 5 days longer based on pre-modern distances. This is highly significant and underlines the necessity for river-specific correction values to model supra-regional networks of pre-modern inland waterways and navigation with higher precision.Highlights:<ul><li>Systematic comparison of old maps and modern geodata to deduce river-specific length correction values to improve supra-regional network models of pre-modern inland navigation.</li><li>Large-scale analytical approach and transferable GIS workflow for flow distance reconstruction with case studies in Southern Germany.</li><li>Length changes of navigated fairways result in pre-modern period travel times up to 24% higher in corrected models.</li></ul>

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Shahkarami, Nazanin. "Fusegates as hydraulic control structures in rivers." Flow Measurement and Instrumentation 71 (March 2020): 101661. http://dx.doi.org/10.1016/j.flowmeasinst.2019.101661.

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PERMINOV, A. V., O. S. ERMOLAEVA, E. V. KUZNETSOVA, and V. V. ILJINICH. "Experience of computer simulation of flood runoff of the Kuban river to the Krasnodar reservoir based on the DWAT model." Prirodoobustrojstvo, no. 4 (2022): 107–13. http://dx.doi.org/10.26897/1997-6011-2022-4-107-113.

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The article is dedicated to PC modeling of the maximum water runoff of the Kuban rivers flowing to the Krasnodar reservoir after the storm rains. A mathematical model of the «precipitation-runoff» type – DWAT was used. This model is recommended by the World Meteorological Organization for use on rivers with flash floods, based on river survey digital elevation models and storm rain forecasts. A possibility of using proposed approach, the estimated possibility of using DWAT for short-term forecasting of flood inflow to the Krasnodar reservoir based on storm precipitation at predictor meteorological stations, which is tentatively assessed based on the analysis of the dependence of the main elements of floods on the storm rain characteristics. In addition to the digital relief model, the model uses georeferenced layers of data on vegetation, land use types and soils of the catchment area. In general, the article shows the process of entering and processing data into the model. The obtained final simulation results, expressed by the forecast hydrograph, are compared with the observed true values. The forecasted flood graphs correspond suffi ciently to the observed ones and in general the ma ximum water discharges of the forecasted floods obtained using the model under study for previous precipitation are for the most part slightly higher than the observed ones, which is partly explained by the spatial data due to map resolution used. The use of more detailed source data and map resolution may improve the final result.

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He, Fei, Qiuying Lai, Jie Ma, Geng Wei, and Weixin Li. "Numerical Simulations of Sudden Oil Spills in Typical Cross-Border Rivers in the Yangtze River Delta Region." Applied Sciences 12, no. 24 (December 19, 2022): 13029. http://dx.doi.org/10.3390/app122413029.

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The Taipu River is an important cross-border river in the Yangtze River Delta region and a direct channel connecting Taihu Lake and Huangpu River. Along the main stream of the Taipu River are many sources of water, such as the Wujiang, Dingzha, and Liantang Rivers. Many boats traverse these rivers transporting a wide variety of goods, including large quantities of oil, chemicals, and other dangerous goods. In the event of accidents on these vessels, spilled cargo will directly threaten the drinking water safety of people in the region. Aiming at simulating and assessing the environmental risks of sudden oil spills in rivers in the Yangtze River Delta region, this paper established a two-dimensional oil spill model of the typical transboundary Taipu River based on the MIKE21 water environment numerical simulation software developed by the Danish Institute of Water Conservancy. The established model will improve emergency response and treatment plans as well as our understanding of river oil spill progressions.

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Al-Masgari, Abd Al-Salam, Mohamed Elsaadany, Numair A. Siddiqui, Abdul Halim Abdul Latiff, Azli Abu Bakar, Sami Elkurdy, Maman Hermana, Ismailalwali Babikir, Qazi Sohail Imran, and Teslim Adeleke. "Geomorphological Geometries and High-Resolution Seismic Sequence Stratigraphy of Malay Basin’s Fluvial Succession." Applied Sciences 11, no. 11 (June 2, 2021): 5156. http://dx.doi.org/10.3390/app11115156.

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This study identified the Pleistocene depositional succession of the group (A) (marine, estuarine, and fluvial depositional systems) of the Melor and Inas fields in the central Malay Basin from the seafloor to approximately −507 ms (522 m). During the last few years, hydrocarbon exploration in Malay Basin has moved to focus on stratigraphic traps, specifically those that existed with channel sands. These traps motivate carrying out this research to image and locate these kinds of traps. It can be difficult to determine if closely spaced-out channels and channel belts exist within several seismic sequences in map-view with proper seismic sequence geomorphic elements and stratigraphic surfaces seismic cross lines, or probably reinforce the auto-cyclic aggregational stacking of the avulsing rivers precisely. This analysis overcomes this challenge by combining well-log with three-dimensional (3D) seismic data to resolve the deposition stratigraphic discontinuities’ considerable resolution. Three-dimensional (3D) seismic volume and high-resolution two-dimensional (2D) seismic sections with several wells were utilized. A high-resolution seismic sequence stratigraphy framework of three main seismic sequences (3rd order), four Parasequences sets (4th order), and seven Parasequences (5th order) have been established. The time slice images at consecutive two-way times display single meandering channels ranging in width from 170 to 900 m. Moreover, other geomorphological elements have been perfectly imaged, elements such as interfluves, incised valleys, chute cutoff, point bars, and extinction surfaces, providing proof of rapid growth and transformation of deposits. The high-resolution 2D sections with Cosine of Phase seismic attributes have facilitated identifying the reflection terminations against the stratigraphic amplitude. Several continuous and discontinuous channels, fluvial point bars, and marine sediments through the sequence stratigraphic framework have been addressed. The whole series reveals that almost all fluvial systems lay in the valleys at each depositional sequence’s bottom bars. The degradational stacking patterns are characterized by the fluvial channels with no evidence of fluvial aggradation. Moreover, the aggradation stage is restricted to marine sedimentation incursions. The 3D description of these deposits permits distinguishing seismic facies of the abandoned mud channel and the sand point bar deposits. The continuous meandering channel, which is filled by muddy deposits, may function as horizontal muddy barriers or baffles that might isolate the reservoir body into separate storage containers. The 3rd, 4th, and 5th orders of the seismic sequences were established for the studied succession. The essential geomorphological elements have been imaged utilizing several seismic attributes.

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Suzuki, M., K. Chihara, M. Okada, H. Kawashima, and S. Hoshino. "Development of Dialog System Model for Eutrophication Control between Discharging River Basin and Receiving Water Body – Case Study of Lake Sagami (Japan)." Water Science and Technology 21, no. 12 (December 1, 1989): 1821–24. http://dx.doi.org/10.2166/wst.1989.0178.

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A computer program based on expert system software was developed and proposed as a prototype model for water management to control eutrophication problems in receiving water bodies (Suzuki etal., 1988). The system has several expert functions: 1. data input and estimation of pollution load generated and discharged in the river watershed; 2. estimation of pollution load run-off entering rivers; 3. estimation of water quality of receiving water bodies, such as lakes; and 4. assisting man-machine dialog operation. The program can be used with MS-DOS BASIC and assembler in a 16 bit personal computer. Five spread sheets are utilized in calculation and summation of the pollutant load, using multi-windows. Partial differential equations for an ecological model for simulation of self-purification in shallow rivers and simulation of seasonal variations of water quality in a lake were converted to computer programs and included in the expert system. The simulated results of water quality are shown on the monitor graphically. In this study, the expert system thus developed was used to estimate the present state of one typical polluted river basin. The river was the Katsura, which flows into Lake Sagami, a lake dammed for water supply. Data which had been actually measured were compared with the simulated water quality data, and good agreement was found. This type of expert system is expected to be useful for water management of a closed water body.

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Zhao, Nannan, Alireza Ghaemi, Chengwen Wu, Shahab S. Band, Kwok-Wing Chau, Atef Zaguia, Majdi Mafarja, and Amir H. Mosavi. "A decomposition and multi-objective evolutionary optimization model for suspended sediment load prediction in rivers." Engineering Applications of Computational Fluid Mechanics 15, no. 1 (January 1, 2021): 1811–29. http://dx.doi.org/10.1080/19942060.2021.1990133.

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Zinoviev, A. T., A. V. Dyachenko, K. B. Koshelev, and K. V. Marusin. "Modeling of channel processes in large rivers with the use of field data." EURASIAN JOURNAL OF MATHEMATICAL AND COMPUTER APPLICATIONS 9, no. 1 (2021): 87–102. http://dx.doi.org/10.32523/2306-6172-2021-9-1-87-102.

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The paper deals with mathematical description of channel processes occurring in long sections of large rivers with a complex morphometry. To forecast negative manifestations of channel deformations, a computer model of river sediment transport in the study section is proposed. It is based on a three-dimensional (3D) / two-dimensional horizontal (2DH) flow model, a 2DH model of bed sediment transport and observation data. Comparative analysis of simulation results of channel processes in the Ob river section at the Barnaul water intakes and in situ data makes it possible to evaluate forecast capabilities of the designed model, in particular, for quantitative assessment of changes in channel topography of the study section caused by natural and anthropogenic impacts.

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Abraham, Dulcy M., and Daniel W. Halpin. "Simulation of the construction of cable-stayed bridges." Canadian Journal of Civil Engineering 25, no. 3 (June 1, 1998): 490–99. http://dx.doi.org/10.1139/l97-109.

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Cable-stayed bridges are ideal for spanning natural barriers of wide rivers, deep valleys, or ravines, and for pedestrian bridges crossing wide interstate highways. Modern construction of cable-stayed bridges makes use of the segmental balanced cantilever techniques and involves many repetitive cycles of placing the concrete segments (both cast-in-place and precast) and supporting cables. It provides a fertile area for the application of computer simulation techniques for the planning and analysis of the process, particularly for studying the interaction of resources used in the construction phase and also for assessing the productivity of the construction processes. This paper employs MicroCYCLONE, a microcomputer-based simulation program, for the modeling and simulation of the construction of two cable-stayed bridges: the Dame Point Bridge in the state of Florida, U.S.A., and the Tsukuhara Bridge in Hyuougo, Japan. The paper will also provide a brief explanation of the suspended long traveler method used on the Tsukuhara Bridge, the simulation models developed to analyze the construction processes, and the results of sensitivity analyses.Key words: simulation, modeling, construction, cable-stayed bridges, resources, productivity, balanced cantilever construction.

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Du, Chongjiang. "An element-free Galerkin method for simulation of stationary two-dimensional shallow water flows in rivers." Computer Methods in Applied Mechanics and Engineering 182, no. 1-2 (February 2000): 89–107. http://dx.doi.org/10.1016/s0045-7825(99)00087-0.

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Mohan, C. Leela, and K. Ch Sri Kavya, K Sarat Kumar. "Performance Exploration of Uncertain RF MEMS Switch Design with Uniform Meanders." International Journal of Communication Networks and Information Security (IJCNIS) 14, no. 2 (August 31, 2022): 66–82. http://dx.doi.org/10.17762/ijcnis.v14i2.5480.

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The design of RF-MEMS Switch is useful for future artificial intelligence applications. Radio detection and range estimation has been employed with RF MEMS technology. Attenuators, limiters, phase shifters, T/R switches, and adjustable matching networks are components of RF MEMS. The proposed RF MEMS technology has been introduced in T/R modules, lenses, reflect arrays, sub arrays and switching beam formers. The uncertain RF MEMS switches have been faced many issues like switching and voltage alterations. This study aims in the direction of design, simulation, model along with RF MEMS switching analysis including consistent curving or meandering. The proposed RF MEMS Switch is a flexure form of the Meanders that attain minimal power in nominal voltage. Moreover, this research work highlights the materials assortment in case of beam along with signal-based dielectric. The performance analysis is demonstrated for various materials that have been utilized in the design purpose. Further, better isolation is accomplished at the range of -31dB necessary regarding 8.06V pull-in voltage through a spring constant valued at 3.588N/m, switching capacitance analysis has been found to be 103 fF at ON state and 7.03pF at OFF state and the proposed switch is optimized to work at 38GHz. The designed RF MEMS switch is giving 30% voltage improvement; switching frequency is improved by 21.32% had been attained, which are outperformance the methodology and compete with present technology.

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Lakshman Rao, P., B. Sree Sai Prasad, Anurag Sharma, and Kishanjit Kumar Khatua. "Experimental and numerical analysis of velocity distribution in a compound meandering channel with double layered rigid vegetated flood plains." Flow Measurement and Instrumentation 83 (March 2022): 102111. http://dx.doi.org/10.1016/j.flowmeasinst.2021.102111.

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Zinoviev, Alexander T., Alexander V. Dyachenko, Konstantin B. Koshelev, and Konstantin V. Marusin. "MODELING AND FIELD OBSERVATIONS OF CHANNEL PROCESSES OF THE SIBERIAN RIVERS. OB RIVER AT BARNAUL CITY SITE AS A CASE STUDY." Interexpo GEO-Siberia 4, no. 1 (May 21, 2021): 126–36. http://dx.doi.org/10.33764/2618-981x-2021-4-1-126-136.

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Computer simulation of channel morphodynamic for the section of a large river in real unsteady hydrological conditions is conducted. The Ob river channel section at Barnaul city is investigated. At the site considered the channel processes cause serious hazard to some important structures such as the municipal water intake and the power line. The time of modeling covers the period from the flood peak to the low water stage. The simulation is implemented by means of Delft3D program suite. The sediment transport is calculated by two types of Van Rijn’s formula (1984 and 1993). The simulation results are verified by the field data collected at the study site over the same time period. These results show poor agreement with the field data. The river bed erosion spatial pattern modeled differs from the real one significantly. Probably a reason of this discrepancy is that the formula used can’t estimate the sediment transport value correctly.

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Filimonov, Valeriy Yu, Alexander T. Zinoviev, and Olga V. Lovtskaya. "Method for estimating the pollutant flow rate under diffuse pollution of small lowland rivers." Mathematics and Computers in Simulation 182 (April 2021): 807–18. http://dx.doi.org/10.1016/j.matcom.2020.12.003.

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Galinos, Christos, Jonas Kazda, Wai Hou Lio, and Gregor Giebel. "T2FL: An Efficient Model for Wind Turbine Fatigue Damage Prediction for the Two-Turbine Case." Energies 13, no. 6 (March 11, 2020): 1306. http://dx.doi.org/10.3390/en13061306.

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Wind farm load assessment is typically conducted using Computational Fluid Dynamics (CFD) or aeroelastic simulations, which need a lot of computer power. A number of applications, for example wind farm layout optimisation, turbine lifetime estimation and wind farm control, requires a simplified but sufficiently detailed model for computing the turbine fatigue load. In addition, the effect of turbine curtailment is particularly important in the calculation of the turbine loads. Therefore, this paper develops a fast and computationally efficient method for wind turbine load assessment in a wind farm, including the wake effects. In particular, the turbine fatigue loads are computed using a surrogate model that is based on the turbine operating condition, for example, power set-point and turbine location, and the ambient wind inflow information. The Turbine to Farm Loads (T2FL) surrogate model is constructed based on a set of high fidelity aeroelastic simulations, including the Dynamic Wake Meandering model and an artificial neural network that uses the Bayesian Regularisation (BR) and Levenberg–Marquardt (LM) algorithms. An ensemble model is used that outperforms model predictions of the BR and LM algorithms independently. Furthermore, a case study of a two turbine wind farm is demonstrated, where the turbine power set-point and fatigue loads can be optimised based on the proposed surrogate model. The results show that the downstream turbine producing more power than the upstream turbine is favourable for minimising the load. In addition, simulation results further demonstrate that the accumulated fatigue damage of turbines can be effectively distributed amongst the turbines in a wind farm using the power curtailment and the proposed surrogate model.

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BERKE, JÓZSEF. "MEASURING OF SPECTRAL FRACTAL DIMENSION." New Mathematics and Natural Computation 03, no. 03 (November 2007): 409–18. http://dx.doi.org/10.1142/s1793005707000872.

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There were great expectations in the 1980s in connection with the practical applications of mathematical processes which were built mainly upon the fractal dimension, mathematical basis. Results were achieved in the first times in several fields: examination of material structure, simulation of chaotic phenomena (earthquake, tornado), modeling real processing with the help of the information technology and its equipments, the definition of the length of rivers or riverbanks. Significant results were also achieved later in practical applications in the fields of information technology, certain image processing areas, data compression, and computer classification. In this paper, the well known algorithms calculating fractal dimension in a much simplified manner will be presented. The novel mathematical concepts, named by the author as 'Spectral Fractal Dimension' are also described in this paper.

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Journal articles on the topic 'Meandering rivers Computer simulation'

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