基于反馈力浸入边界法模拟复杂动边界流动

浸入边界法是模拟流固耦合的重要数值方法之一。本文采用反馈力浸入边界方法,对旋转圆柱和水轮机活动导叶旋转摆动绕流后的动边界流场进行数值模拟。其中,固体边界采用一系列离散的点近似代替,流体为不可压缩牛顿流体,使用笛卡尔自适应加密网格,利用有限差分法进行求解。固体对流场的作用通过构造适宜的反馈力函数实现。本文首先通过旋转圆柱绕流的计算结果同实验结果进行对比,吻合较好,验证了该计算方法的可靠性。然后针对水电站水力过渡过程中水轮机活动导叶旋转摆动绕流后的动边界流场进行数值模拟,得到导叶动态绕流后的流场分布特性和涡结构的演化特性。

Numerical simulation on complex moving boundary flow using feedback immersed boundary method

Immersed boundary method is one of the important numerical methods for solving the interaction between solid and viscous fluid.A rotating cylinder and a swirl guide vane of hydro-turbine immersed in an incompressible fluid are simulated using finite difference immersed boundary method combined with feedback force method.The immersed boundary is replaced by a set of discrete material points and an adaptive refined.The fluid domain is discretized by Cartesian grid with finite difference.The force action on the fluid due to the solid is constructed by the feedback force function.Two numerical examples are implemented,one is a rotating cylinder immersed in an incompressible fluid.Comparisons between the results of the paper and that of experiment show the reliability of this method.Another is the swirl of guide vane of hydro-turbine in water,the dynamical flow characteristics is gained,and the evolution of vortex is also shown.