采用数值模拟方法研究了复式断面和矩形断面60°弯道明渠的流场结构。自由水面的捕捉采用VOF(Volume of Fluid)法,雷诺时均N-S方程采用雷诺应力模型封闭。对两种断面渠型水力特性的模拟结果进行了比较,结果表明:复式断面弯道明渠在...采用数值模拟方法研究了复式断面和矩形断面60°弯道明渠的流场结构。自由水面的捕捉采用VOF(Volume of Fluid)法,雷诺时均N-S方程采用雷诺应力模型封闭。对两种断面渠型水力特性的模拟结果进行了比较,结果表明:复式断面弯道明渠在弯道横断面上存在着多涡结构;滩地上的流速大于主槽上的流速;凹岸和凸岸上的自由液面水位差要比矩形断面的小;水流在渠底的横向运动强度要比矩形断面的大;弯道内外侧的压力差也与矩形断面有所不同。展开更多
The three-demensional turbulent flow in a stirred vessel driven by a Rushton turbine was simulated by using the anisotropic differential Reynolds stress model (RSM).The effect of the turbulent model, modeling approach...The three-demensional turbulent flow in a stirred vessel driven by a Rushton turbine was simulated by using the anisotropic differential Reynolds stress model (RSM).The effect of the turbulent model, modeling approach and discretization scheme on mean velocities and turbulent kinetic energy was investigated.The RSM was found to give vortex structure and positions near the blade reasonably.The two peak distribution of turbulent intensity near the blade tip could be effectively reflected by both the RSM and the anisotropic k-ε model;however the predicted results of velocity fluctuations by the RSM and the sliding mesh approach showed better agreement with the reported experimental data than by the anisotropic k-ε model and the multiple reference frames(MRF)approach, and the simulated turbulent kinetic energy was still under-predicted by the RSM.The simulated results validated by reported experimental data showed that the prediction ability for turbulent flow by the QUICK scheme approached second-order upwind scheme’s ability and both of them were better than first-order precision schemes.展开更多
文摘采用数值模拟方法研究了复式断面和矩形断面60°弯道明渠的流场结构。自由水面的捕捉采用VOF(Volume of Fluid)法,雷诺时均N-S方程采用雷诺应力模型封闭。对两种断面渠型水力特性的模拟结果进行了比较,结果表明:复式断面弯道明渠在弯道横断面上存在着多涡结构;滩地上的流速大于主槽上的流速;凹岸和凸岸上的自由液面水位差要比矩形断面的小;水流在渠底的横向运动强度要比矩形断面的大;弯道内外侧的压力差也与矩形断面有所不同。
文摘The three-demensional turbulent flow in a stirred vessel driven by a Rushton turbine was simulated by using the anisotropic differential Reynolds stress model (RSM).The effect of the turbulent model, modeling approach and discretization scheme on mean velocities and turbulent kinetic energy was investigated.The RSM was found to give vortex structure and positions near the blade reasonably.The two peak distribution of turbulent intensity near the blade tip could be effectively reflected by both the RSM and the anisotropic k-ε model;however the predicted results of velocity fluctuations by the RSM and the sliding mesh approach showed better agreement with the reported experimental data than by the anisotropic k-ε model and the multiple reference frames(MRF)approach, and the simulated turbulent kinetic energy was still under-predicted by the RSM.The simulated results validated by reported experimental data showed that the prediction ability for turbulent flow by the QUICK scheme approached second-order upwind scheme’s ability and both of them were better than first-order precision schemes.
