混合网格化学非平衡绕流通量分裂格式及并行算法

讨论了非结构混合网格上的二阶VanLeer逆风矢通量分裂格式,并将其应用于三维高超声速化学非平衡粘性流场的并行计算.高超声速绕流的复杂性要求对N-S方程求解的数值模拟方法应具有较高的计算精度及效率.我们针对混合网格上的有限体积格心格式,引入辅助点方法建立了具有空间二阶精度的VanLeer逆风矢通量分裂格式,提高了数值格式的模拟精度,并采用分布式并行化计算技术用以提高计算效率.粘性通量的计算采用中心格式,化学非平衡动力学模型为7组元空气反应模型,采用考虑了化学反应特征时间的当地时间步长显式Runge-Kutta时间推进格式.对三维双椭球外形的高超声速粘性流场进行了并行计算,获得满意的结果.

Upwind flux vector splitting scheme for chemical non-equilibrium flows on hybrid meshes and its parallelization

The second order VanLeer flux vector splitting scheme on unstructured hybrid meshes was discussed and implemented to the simulation of hypersonic chemical non equilibrium flows with parallel computing on PCs-Cluster. The complexity of the hypersonic flows with chemical non-equilibrium effects needs solvers of N S equations with high accuracy and high performance. An auxiliary point method was introduced to constitute the 2nd order VanLeer flux vector splitting cell-center scheme, and the distributed parallel computing technique to improve the computation efficiency. The viscous flux was calculated using central scheme and the chemical kinetic model was 7 species air model. The explicit 5-step Runge-Kutta time step method was used with the consideration of chemical reaction characteristic time. This scheme was implemented to the simulation of the hypersonic flows around a 3D bi-ellipse model. Numerical results were obtained and compared with the references.