有限体积格子Boltzmann方法用于近空间连续流区绕流模拟

Flow Simulation in Near Space Continuum Regime Using Finite Volume Lattice Boltzmann Method

针对航天器再入解体形成残骸碎片的近空间绕流计算问题,拓展了格子Boltzmann方法在可压缩流动模拟的能力。引入有限体积隐式格式求解耦合双分布函数格子Boltzmann模型方程及采用圆函数为基础构造的D2Q13离散速度模型;引入IMEX-RK格式进行了时间项离散解决模型方程的源项刚性问题;对Riemann问题、平板双马赫反射问题、RAE2822翼型跨声速绕流等近空间连续流区、可压缩典型案例进行了数值模拟。通过比较分析,初步验证了耦合双分布函数有限体积格子Boltzmann方法对连续流区、可压缩流动的模拟能力;进一步开展了方柱形解体残骸的超声速绕流模拟,得到与N-S方程计算结果吻合一致的绕流结果,证实经改进的耦合双分布函数有限体积格子Boltzmann方法对解体残骸碎片绕流问题具有较好的模拟能力。

To simulate the flow around the debris of spacecraft disintegrated in near space,it is necessary to improve the capability of Lattice Boltzmann Method for the compressible flow.The finite volume implicit scheme was introduced to solve the coupled double distribution function Lattice Boltzmann equations and the D2Q13 lattice model originated from the circle function.To deal with the stiffness of source term in the model equations,the IMEX-RK scheme was employed for temporal discretization.Some typical problems including the Riemann problem,the double-Mach-reflection problem,and the transonic flow around airfoil were solved by the present method.The simulation results verified its great potential in high speed compressible flows.Furthermore,simulation of the supersonic flow around the square cylinder like debris was carried out.Results were in good agreement with that of N-S equation and the ability of the improved finite volume double distribution function Lattice Boltzmann method in the simulation of flow around spacecraft debris was verified.