计算网格对气动力气动热数值模拟影响的研究

以二维圆柱钝头超声速流场为研究对象,应用计算流体力学方法研究了计算网格在气动力及气动热数值模拟中的影响.计算程序中对流项、扩散项分别采用AUSM格式和中心差分格式离散,并用多步Runge-Kutta显式时间推进法求解空间离散后的控制方程.计算结果表明,壁面法向第一层网格间距、网格长宽比以及扩张度等因素都会对壁面摩阻、热流的计算产生影响,尤其是壁面法向第一层网格间距影响最为突出.边界层的计算结果与实验数据进行了仔细对比,包括壁面压力分布,摩阻系数Cf分布,斯坦顿数St分布等.高马赫数滞止气流导致壁面附近产生巨大速度梯度以及温度梯度,这些梯度的准确计算需要合适的壁面法向第一层网格间距以及合理的网格长宽比、扩张度.

Grid Study on Numerical Simulation of Aerodynamic flowfield

Numerical simulation of two-dimesional cylinder blunt hypersonic flowfield is conducted by means of computational fluid dynamic method.Mesh influences are studied in present calculation.In our procedure,convection terms and diffusion terms are calculated using AUSM(Advection Upwind Splitting Method)scheme and CD(Center Difference)scheme,respectively.The Runge-Kutta time marching method is employed to slove space discrete control equations.The frist normal grid space,length-width ratio and expansion ratio affect numerical simulation,especial normal grid space on the sylinder wall.Comparison between the computational results and experimental values are carried out including surface pressure coefficients Cp and Stanton number St.Accurate calculation for the great velocity and temperature gradients is the primary reason that strictly request grid quality.