hSimulation of flexible filaments in a uniform flow by the immersed boundary method
hSimulation of flexible filaments in a uniform flow by the immersed boundary method
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DOI：
10.1016/j.jcp.2007.07.002
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发表时间：
2007-10-01
影响因子：
4.1
通讯作者：
Sung, Hyung Jin
中科院分区：
文献类型：
--
作者：
Huang, Wei-Xi;Shin, Soo Jai;Sung, Hyung Jin
本文提出了一种改进的浸没边界（IB）方法，用于模拟均匀流中的柔性细丝。所提出的IB方法是基于一个有效的Navier-Stokes求解器，采用分步方法和交错笛卡尔网格系统。定义在欧拉网格上的流体运动和定义在拉格朗日网格上的细丝运动被独立地求解，并且它们的相互作用力使用反馈定律被明确地计算。本文提出了一种直接数值方法来计算不可伸长约束下的细丝运动。当应用到类似于绳摆的摆动细丝的情况下，所提出的方法给出的结果非常相似的解析解使用摄动法。研究了均匀流场中柔性细丝拍动产生小涡的机理。通过改变纤维长度观察了系统的阻尼特性，并研究了固定端（简支或固支）边界条件的影响。对于均匀流中的两个并排的细丝，在本模拟中再现了同相拍动和异相拍动。排斥力包括在配方中，以处理经历异相扑动的并排长丝的自由端之间的碰撞。(c)2007年爱思唯尔公司All rights reserved.
An improved version of the immersed boundary (IB) method is developed for simulating flexible filaments in a uniform flow. The proposed IB method is based on an efficient Navier-Stokes solver adopting the fractional step method and a staggered Cartesian grid system. The fluid motion defined on an Eulerian grid and the filament motion defined on a Lagrangian grid are independently solved and their interaction force is explicitly calculated using a feedback law. A direct numerical method is developed to calculate the filament motion under the constraint of inextensibility. When applied to the case of a swinging filament analogous to a rope pendulum, the proposed method gave results very similar to those of the analytical solution derived using the perturbation method. For a flexible filament flapping in a uniform flow, the mechanism by which small vortex processions are produced was investigated. The bistable property of the system was observed by altering the filament length, and the effects of the boundary condition at the fixed end (simply supported or clamped) were studied. For two side-by-side filaments in a uniform flow, both in-phase flapping and out-of-phase flapping were reproduced in the present simulations. A repulsive force was included in the formulation to handle collisions between the free ends of side-by-side filaments undergoing out-of-phase flapping. (c) 2007 Elsevier Inc. All rights reserved.