带横隔板圆柱绕流特性数值模拟

Numerical simulation of the characteristics of flow past circular cylinder with splitter plate

为揭示尾迹区添加横隔板对圆柱绕流流场特性影响,把多步格式引入到特征线算子分裂有限元法中,建立了基于多步格式的特征线算子分裂有限元法:在每个时间步内将Navier-Stokes方程分裂成对流项和扩散项,对流项时间离散采用多步格式,在每一子时间步内沿特征线展开并显式求解。方腔流数值模拟结果表明该算法既可降低对整体时间步长的要求又可提高计算精度。对比有无横隔板圆柱绕流流场和圆柱表面压力变化表明,横隔板可以有效地抑制绕流尾迹区涡旋脱落,提高圆柱背流面压力,减少圆柱上下表面的压力差。

A multistep characteristic-based operator-splitting finite element method is proposed to determine the effects of adding a splitter plate at the back of a cylinder on the characteristics of a flow past a circular cylinder. In each time step,the N-S equations are split into diffusive and convective parts. For the convective part,temporal discretization is performed by the characteristic Galerkin method with a multistep technique. Results of the present model are in good agreement with previously published data. Thus,the present model is competitive in solving incompressible viscous flows in terms of accuracy and efficiency. Furthermore,the flow past a circular cylinder with a splitter plate was simulated by the present model. The flow fields and pressure on the cylinder surface with and without a splitter plate were compared. Findings indicated that the plate can suppress vortex shedding,increase the pressure on the leeward of the cylinder,and reduce the pressure difference between the upper and lower surfaces.