基于波尔兹曼方法研究幂律流体的椭圆柱绕流

LATTICE BOLTZMANN SIMULATION OF POWER-LAW FLOW PAST AN ELLIPTIC CYLINDER

  • 摘要: 基于格子波尔兹曼方法(lattice Boltzmann method) 和幂律流体本构方程, 建立二维流动模型, 将充分发展的速度分布与理论解进行对比, 吻合良好. 对幂律流体的圆柱绕流进行模拟, 采用了反弹格式的无滑移圆柱边界, 并使用应力积分法计算阻力系数, 分析了稳态圆柱绕流时, 阻力系数随幂律指数n 以及雷诺数Re 的变化规律. 分析了椭圆横轴/纵轴长度比和幂律指数n, 对压力系数Cp 和黏度系数Cv 的影响. 得到的变化规律与有限元方法规律一致, 验证了格子波尔兹曼模型的可行性.

     

    Abstract: Based on Lattice Boltzmann method and constitutive equation for power-law fluid, a model for flow in a channel is proposed, and the fully development velocity of outflow obtained is in good agreement with the analytic solution. A simulation of power-law fluid past a cylinder is carried out, where the bounce-back boundary scheme is adopted for non-slip velocity at the circular cylinder surface. The drag coeficient is calculated by integrating the total stresses on the boundary of the circular cylinder, the effect of power-law index and Re on the drag coeficient is further analyzed. For elliptic cylinder, the influences of different shapes and power-law indexes on the pressure coeficient and viscosity coeficient are investigated. The model is validated by the good agreement between the simulation results and those obtained by other numerical simulation methods.

     

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