低速流预处理Roe格式中的数值粘性

使用Roe格式计算低马赫数流动,需采用预处理技术.在预处理技术中,需要选择适合的预处理参数,但有时很难找到,因而得不到合理的计算结果.通过数值实验,发现使用预处理方法时,格式的数值粘性对低速流动的模拟有显著的影响.提出了在预处理Roe格式中加入可调参数,用以控制数值粘性对计算结果的影响.带有可调节数值粘性参数的预处理Roe格式的数值粘性更接近低速流动的真实耗散,反映了低速流动的真实物理现象.对方腔流动和圆柱绕流的低雷诺数定常流动所做的数值实验,得到了比较满意的结果,表明这一改进是有效的.对同一低雷诺数不同低马赫数的定常圆柱绕流所做的数值实验,均得到了满意的结果,表明了方法的适用性.

Numerical dissipation of Roe's scheme with preconditioning for low-speed flows

Preconditioning is necessary for simulating of low-speed flows with Roe-s scheme. With most research on choosing preconditioning parameter, the solution may be wrong. Numerical experiments show the numerical dissipation of the scheme has a notable effect on low-speed flow numerical simulation with preconditioning method. A manner by using an adjustable parameter in preconditioning Roe-s scheme to control the numerical dissipation was proposed. The numerical dissipation of preconditioning Roe-s scheme with an adjustable parameter was more similar to the real dissipation of low-speed flows and reflected the real physical phenomena of low-speed flows. Numerical results show the efficiency of the new scheme and the low Reynold-number steady solutions of viscous flow past a circular cylinder and square cavity flow are satisfied. Also indicate that the applicability of the new scheme and different low Mach number with the same low Reynold-number steady solutions of viscous flow past a circular cylinder are also satisfied.