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针对近空间高超声速流场的特点,采用Van Leer格式对直接模拟蒙特卡洛-信息保存(DSMCIP)方法质量守恒方程中的计算格式进行改进.将局部马赫数作为分裂通量的标准,并重构单元分界面两侧的左右输运通量,使得计算格式具有通量分裂的特点,解决了DSMC-IP方法在高超声速流场计算中的应用问题.将改进后的通量分裂型DSMC-IP方法引入非结构网格中,对二维近空间高超声速流场进行数值模拟.计算结果表明:通量分裂型DSMC-IP方法所得出的数值结果与实验值及参考值符合较好,明显降低了直接模拟蒙特卡洛(DSMC)方法所带来的统计耗散.当来流气体的稀薄程度增加时,其非平衡效应也更加明显,而通量分裂型DSMC-IP方法的计算结果与参考值相差均在10%以内,良好地反映了非平衡条件下的流场特征,验证了通量分裂型DSMC-IP方法的可行性和有效性.
Aiming at the characteristics of near-space hypersonic flow field, the Van Leer format is used to improve the calculation formula in the mass-conservation equation of direct simulation Monte Carlo-Information Preservation (DSMCIP) method. The local Mach number is taken as the criterion of split flux, The left and right transport fluxes on both sides of the unit interface make the calculation format have the characteristics of flux splitting, which solves the application of DSMC-IP method in hypersonic flow field calculation.The improved flux splitting DSMC- IP method was introduced into the unstructured grid to simulate the two-dimensional hypersonic flowfield in near-space. The calculated results show that the numerical results obtained by flux-split DSMC-IP method are in good agreement with the experimental values and reference values Reduces the statistical dissipation caused by the Direct Simulation Monte Carlo method (DSMC), and the non-equilibrium effect is more obvious when the inflow of gas is lean, and the calculation results of flux-splitting DSMC-IP The difference of reference value is less than 10%, which reflects the characteristics of flow field well under unbalanced condition and verifies the feasibility and effectiveness of the flux splitting DSMC-IP method.