A 2-D Lattice Boltzmann Method（LBM） coupled with a Sub-Grid Stress（SGS） model is proposed and validated by flows around a non-submerged spur dike in a channel.And then the LBM-SGS model is further applied to flows...A 2-D Lattice Boltzmann Method（LBM） coupled with a Sub-Grid Stress（SGS） model is proposed and validated by flows around a non-submerged spur dike in a channel.And then the LBM-SGS model is further applied to flows in a pumping-station forebay.Shallow water equations are numerically solved by the LBM and the turbulence can be taken into account and modeled efficiently by the Large Eddy Simulation（LES） model.The bounce-back scheme of the non-equilibrium part of the distribution function is used at the inlet boundary,the normal gradient of the distribution function is set as zero at the outlet boundary and the bounce-back scheme is applied to the solid wall to ensure non-slip boundary conditions.Firstly,the model successfully predicts the flow characteristics around a spur dike,such as circulating flow,velocity and water depth distributions.The results are verified by the experimental data and compared to the results obtained by conventional Smagoringsky Model（SM） of LES.Finally,the LBM-SGS model is used to further predict the flow characteristics in a forebay,such as secondary flow and water level.The comparisons show that the model scheme has the capacity to simulate complex flows in shallow water with reasonable accuracy and reliability.展开更多
Hydroelectric facilities impact water temperature; low velocities in a reservoir increase residence time and enhance heat exchange in surface layers. In this study, an unsteady three-dimensional model was developed to...Hydroelectric facilities impact water temperature; low velocities in a reservoir increase residence time and enhance heat exchange in surface layers. In this study, an unsteady three-dimensional model was developed to predict the temperatm＇e dynamics in the McNary Dam forebay. The model is based on the open-source code OpenFOAM. RANS equations with the Boussinesq approximation were used to solve the flow field. A： realizable k-ε model that accounts for the production of wind turbulence was developed. Solar radiation and convective heat transfer at the free surface were included. The result of the model was compared with the field data collected on August 18, 2004. Changes in diurnal stratification were adequately predicted by the model. Observed vertical and lateral temperature distributions were accurately captured. Results indicate that the model can be used as a numerical tool to assess structural and operational alternatives to reduce the forebay temperature.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50779069)the Beijing Natural Science Foundation (Grant No. 3083022)+3 种基金the Open Fund of Key Laboratory of Yellow River Sediment Research of the Ministry of Water Resources (Grant No. 200903)the National Science and Technology Supporting Programs in the 11th Five-Year Plan (Grant No. 2006BAB06B02)the Chinese Universities Scientific Fund (Grant Nos. 2009-1-90, 2009-2-12)the Program for Changjiang Scholars and Innovative Research Team in University (Grant No. PCSIRT0657)
文摘A 2-D Lattice Boltzmann Method（LBM） coupled with a Sub-Grid Stress（SGS） model is proposed and validated by flows around a non-submerged spur dike in a channel.And then the LBM-SGS model is further applied to flows in a pumping-station forebay.Shallow water equations are numerically solved by the LBM and the turbulence can be taken into account and modeled efficiently by the Large Eddy Simulation（LES） model.The bounce-back scheme of the non-equilibrium part of the distribution function is used at the inlet boundary,the normal gradient of the distribution function is set as zero at the outlet boundary and the bounce-back scheme is applied to the solid wall to ensure non-slip boundary conditions.Firstly,the model successfully predicts the flow characteristics around a spur dike,such as circulating flow,velocity and water depth distributions.The results are verified by the experimental data and compared to the results obtained by conventional Smagoringsky Model（SM） of LES.Finally,the LBM-SGS model is used to further predict the flow characteristics in a forebay,such as secondary flow and water level.The comparisons show that the model scheme has the capacity to simulate complex flows in shallow water with reasonable accuracy and reliability.
基金supported by Hydro Research Foundation (Grant No. DE-EE0002668)
文摘Hydroelectric facilities impact water temperature; low velocities in a reservoir increase residence time and enhance heat exchange in surface layers. In this study, an unsteady three-dimensional model was developed to predict the temperatm＇e dynamics in the McNary Dam forebay. The model is based on the open-source code OpenFOAM. RANS equations with the Boussinesq approximation were used to solve the flow field. A： realizable k-ε model that accounts for the production of wind turbulence was developed. Solar radiation and convective heat transfer at the free surface were included. The result of the model was compared with the field data collected on August 18, 2004. Changes in diurnal stratification were adequately predicted by the model. Observed vertical and lateral temperature distributions were accurately captured. Results indicate that the model can be used as a numerical tool to assess structural and operational alternatives to reduce the forebay temperature.
