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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。
Taking the two-dimensional cylindrical blunt tip supersonic flow field as the research object, the computational fluid dynamics (CFD) method was used to study the influence of the computational grid on the aerodynamic and aerodynamic numerical simulations. The convection terms and the diffusion terms in the calculation program are discretized by using the AUSM scheme and the central difference scheme, respectively, and the governing equations of the spatial discretization are solved by the explicit time propulsion method of multi-step Runge-Kutta. The calculation results show that the factors such as the first layer grid spacing, the grid aspect ratio and the expansion of the wall normal affect the calculation of wall friction and heat flow, especially the influence of the first layer grid spacing on the wall normal . The boundary layer calculation results are compared with the experimental data carefully, including the wall pressure distribution, the friction coefficient Cf distribution and the Stanton number St distribution. A high Mach number of stagnant air flow results in a huge velocity gradient and a temperature gradient near the wall. Accurate calculations of these gradients require a suitable wall-to-layer spacing of the first layer as well as a reasonable grid aspect ratio, expansion.