虚拟网格法模拟静止或运动并列布置双圆柱绕流现象  

A Ghost Cell Method for Simulating Flows Around Stationary or Moving Twin Cylinders in a Side-by-side Arrangement

作　　者：雷悦[1] 石伏龙 LEI Yue;SHI Fu-Long(School of Transportation,Wuhan University of Technology,Wuhan 430063,China)

机构地区：[1]武汉理工大学交通学院,武汉430063

出　　处：《工程热物理学报》2020年第8期1974-1983,共10页Journal of Engineering Thermophysics

摘　　要：基于自主开发的虚拟网格浸入边界法求解器,数值模拟并列布置双圆柱绕流问题,分析了不同圆柱间距和振荡频率下双圆柱的水动力载荷和尾涡特性。数值算法采用时间半隐式有限差分虚拟网格法,在固定笛卡尔交错网格上求解不可压缩黏性Navier-Stokes方程。在虚拟网格法中,为了考虑任意多体边界对流场的影响,通过设置物体内的虚拟网格单元,采用适当的插值模块及技术重构虚拟网格,以施加浸入动边界条件。首先,数值模拟不同间距下并列布置双圆柱静止绕流问题,分析了不同间距对圆柱表面载荷和水动力特性的影响,捕捉到单涡脱落、偏斜流和双涡脱落等典型流动形态。其次,数值模拟自由流中并列布置圆柱振荡问题,验证了本文方法的精度和模拟多体动边界的准确性和可靠性。最后,分析了不同间距和不同振荡频率下双圆柱的水动力载荷变化规律,观察到不同振荡频率下偏斜流、双涡对称脱落和涡列融合等典型流动干扰现象。The propose of this paper is to simulate incompressible flow around stationary or moving twin cylinders in a side-by-side arrangement by using an in-house developed ghost cell immersed boundary method solver.Further,the effects of the gap size between twin cylinders and the oscillation frequency on the hydrodynamic load and vortex pattern are studied.The numerical model is based on a time semi-implicit finite difference method for the solution of incompressible Navier-Stokes equations on a fixed Cartesian staggered grid.In order to the influence of arbitrary multi-body boundary on the flow field,the ghost cell is reconstructed in the object,and adopting appropriate interpolation modules and techniques to apply the immersive dynamic boundary conditions in the ghost cell immersed boundary method.Based on the present numerical model,flow around twin stationary cylinders in a side-by-side arrangement is simulated.The effects of gap sizes between twin cylinders on the force coefficients are analyzed.Typical vortex patterns are observed such as anti-phase or in-phase synchronized,deflected and single body flow patterns.Then,free stream flow around twin transversely oscillating cylinders is simulated.The present method is demonstrated to be capable of simulating flow around multiple moving bodies.Also,the results show that the average drag coefficient increases slowly with the rising of oscillation frequency.The root-mean-square lift coefficient nearly has no changes when the ratio of oscillation frequency to natural shedding frequency is no more than 1,and it increases significantly when the ratio is larger than 1.In addition,distinct vertex phenomena are observed with the change of oscillation frequency,such as anti-phase or in-phase synchronized,deflected and merged vortex patterns.

关 键 词：浸入边界法 虚拟网格法 动边界 双圆柱绕流 旋涡脱落 

分 类 号：O359[理学—流体力学]