单一贴壁四面体框架绕流场三维数值模拟

Three dimensional numerical simulation of external flow field around tetrahedron frame with a single attached wall

四面体透水框架群作为一种新型的防冲促淤措施已经在各种河流工程中得到推广应用,由于其特殊的几何形状,仅依靠常见的量测手段确定其绕流场结构存在较大困难,使得对该类方法防护机理的理解受到限制。在CFD通用程序Fluent平台上建立三维水动力数值模型,对单一贴壁四面体透水框架的清水流场进行模拟,并与超声测速仪(ADV)实测结果进行对比验证。研究表明该数值模型有效地补充了三维复杂流场的物理实验结果,有助于理解四面体框架的防护机理。改变水力参数,计算得到阻力系数CD相对于雷诺数Re的变化曲线,当Re>105时,单一贴壁四面体框架的阻力系数CD为一常数值,大小为1.557。

The Tetrahedron Frame Groups（TFG） protection method,a new engineering measure to prevent bank erosion and promote sediment deposition,has been widely adopted in many river engineering practices in China.However,due to the unique geometric forms of TFG,it is difficult to measure the external flow in TFG,which limit further understanding about the mechanism of the TFG protection method.A three dimensional（3-D） hydrodynamic model is developed on the platform of the Computational Fluid Dynamics（CFD） platform fluent to simulate the external flow field and drag around the Tetrahedron Frame（TF） with a single attached wall in clear water environment.The simulation results are compared with the Acoustic Doppler Velocimetry（ADV） experimental measurements.The result shows that the 3-D model can effectively supplement the experimental study of the complex flow fields,which provides valuable information for the mechanism study of the TFG protection method.Giving different values of hydraulic parameters,the diagram of drag coefficient CD vs Reynolds number Re is obtained using the 3-D model.The diagram shows that the drag coefficient in TF with a single attached wall tends to be a constant value of 1.557 when the Reynolds number is larger than 105.