Without the ‘rigid lid’ assumption, the depth averaged linear k-ε model can describe the change of water depth. However, it is incapable of accurately simulating turbulent flows, where the normal Reynolds stresses...Without the ‘rigid lid’ assumption, the depth averaged linear k-ε model can describe the change of water depth. However, it is incapable of accurately simulating turbulent flows, where the normal Reynolds stresses play an important role. A depth averaged nonlinear k-ε model is developed taking into account the stress relations described by Speziale. The depth averaged linear and nonlinear k-ε models can both be used to calculate the flow field near a side discharge into open channel flow, but the results of the nonlinear model are in much closer agreement with experimental results. Furthermore, the technique of changing the 2D linear k-ε program into a depth averaged, nonlinear program is presented.展开更多
A 3-D numerical model for calculating flow in non-curvilinear coordinates was established in this article. The flow was simulated by solving the full Reynolds-averaged Navier-Stokes equations with the RNG κ-ε turbul...A 3-D numerical model for calculating flow in non-curvilinear coordinates was established in this article. The flow was simulated by solving the full Reynolds-averaged Navier-Stokes equations with the RNG κ-ε turbulence model. In the horizontal x-y-plane, a boundary-fitted curvilinear co-ordinate system was adopted, while in the vertical direction, a σ co-ordinate transformation was used to represent the free surface and bed topography. The water level was determined by solving the 2-D Poisson equation derived from 2-D depth averaged momentum equations. The finite-volume method was used to discretize the equations and the SIMPLEC algorithm was applied to acquire the coupling of velocity and pressure. This model was applied to simulate the meandering channels and natural rivers, and the water levels and the velocities for all sections were given. By contrasting and analyzing, the agreement with measurements is generally good. The feasibility studies of simulating flow of the natural fiver have been conducted to demonstrate its applicability to hydraulic engineering research.展开更多
A far field numerical model is developed to simulate jet pollution into natural rivers. Its character is to compute the velocity and pollution concentration separately. The velocity is computed by SIMPLEC algorithm i...A far field numerical model is developed to simulate jet pollution into natural rivers. Its character is to compute the velocity and pollution concentration separately. The velocity is computed by SIMPLEC algorithm in boundary fitted coordinate systems. The pollution concentration distribution is computed by developed QUAL IIm and QAIIL 2D program. The present model was applied to the Xiantao section of the Hanjiang River a tributary of Yangtze River, and Xiangjiang River. The flow field and COD distribution are in good agreement with field data.展开更多
文摘Without the ‘rigid lid’ assumption, the depth averaged linear k-ε model can describe the change of water depth. However, it is incapable of accurately simulating turbulent flows, where the normal Reynolds stresses play an important role. A depth averaged nonlinear k-ε model is developed taking into account the stress relations described by Speziale. The depth averaged linear and nonlinear k-ε models can both be used to calculate the flow field near a side discharge into open channel flow, but the results of the nonlinear model are in much closer agreement with experimental results. Furthermore, the technique of changing the 2D linear k-ε program into a depth averaged, nonlinear program is presented.
基金the National Basic Research Program of China (973 Program, Grant No. 2006CB403302)the National Natural Science Foundation of China (Grant No.50779006)the Natural Science Foundation of LiaoningProvince (Grant No. 20062170)
文摘A 3-D numerical model for calculating flow in non-curvilinear coordinates was established in this article. The flow was simulated by solving the full Reynolds-averaged Navier-Stokes equations with the RNG κ-ε turbulence model. In the horizontal x-y-plane, a boundary-fitted curvilinear co-ordinate system was adopted, while in the vertical direction, a σ co-ordinate transformation was used to represent the free surface and bed topography. The water level was determined by solving the 2-D Poisson equation derived from 2-D depth averaged momentum equations. The finite-volume method was used to discretize the equations and the SIMPLEC algorithm was applied to acquire the coupling of velocity and pressure. This model was applied to simulate the meandering channels and natural rivers, and the water levels and the velocities for all sections were given. By contrasting and analyzing, the agreement with measurements is generally good. The feasibility studies of simulating flow of the natural fiver have been conducted to demonstrate its applicability to hydraulic engineering research.
文摘A far field numerical model is developed to simulate jet pollution into natural rivers. Its character is to compute the velocity and pollution concentration separately. The velocity is computed by SIMPLEC algorithm in boundary fitted coordinate systems. The pollution concentration distribution is computed by developed QUAL IIm and QAIIL 2D program. The present model was applied to the Xiantao section of the Hanjiang River a tributary of Yangtze River, and Xiangjiang River. The flow field and COD distribution are in good agreement with field data.
