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

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C_p和黏度系数G_v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.

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 cyhnder is carried out,where the bounce-back boundary scheme is adopted for non-slip velocity at the circular cylinder surface.The drag coefficient 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 coefficient is further analyzed.For elliptic cylinder,the influences of different shapes and power-law indexes on the pressure coefficient and viscosity coefficient are investigated.The model is validated by the good agreement between the simulation results and those obtained by other numerical simulation methods.