用格子Boltzmann模型模拟可压缩完全气体流动

SIMULATIONS OF COMPRESSIBLE PERFECT GAS FLOW BY LATTICE-BOLTZMANN MODELS

  • 摘要: 采用一种新的格子Boltzmann模型模拟超音速流动。在这种模型中,粒子的速度不受限制,可以取得很广。而平衡分布函数的支集却相对集中,使模型得以简化。粒子速度的这种自适应特性允许流体以较高的马赫数流动。通过引入粒子的势能使得该模型适用于具有任意比热比的完全气体。利用Chapman-Enskog方法,从BGK型Boltzmann方程推导出Navier-Stokes方程。在六边形网格上模拟了马赫数为3的前台阶绕流,得到了合理的结果。

     

    Abstract: A new adaptive lattice Boltzmann model is presented to simulate super-sonic flows. Particle velocities may have a large range of values. The support set of equilibrium distributions is determined by the mean velocity and internal energy. The adaptive nature of particle velocities permit the mean flow to have a high Mach number. A particle potential energy is introduced to make the model suitable for the perfect gas with arbitrary specific heat ratio. Navier-Stokes equations are derived by the Chapman-Enskog method from the BGK Boltzmann equation. As numerical test, the simulation is performed for a flow passing over a forward-facing step at Mach number 3 on a hexagonal lattice. The shocks are well captured.

     

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