A stress tensor discontinuity-based immersed boundary-lattice Boltzmann method
A stress tensor discontinuity-based immersed boundary-lattice Boltzmann method
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DOI：
10.1016/j.compfluid.2018.03.027
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发表时间：
2018-08
影响因子：
2.8
通讯作者：
Kosuke Suzuki;M. Yoshino
中科院分区：
文献类型：
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作者：
Kosuke Suzuki;M. Yoshino
利用应力张量的不连续性，我们提出了一种浸入边界格子Boltzmann方法。在浸入边界法中，施加于无滑移边界条件的体积力等效于应力张量在边界上的不连续性。在该方法中，边界由独立于背景格点的拉格朗日点表示，应力张量的不连续性由满足无滑移边界条件的粒子分布函数在这些点上计算得到.用这种方法，我们可以由流体一侧的应力张量除以边界得到局部作用在边界上的力，而在计算作用在边界上的合力和力矩时，不需要考虑内部质量效应。据我们所知，目前的方法是第一个使我们能够计算的应力张量的扩散界面方法类的边界。为了验证本方法的有效性，我们将其应用于典型的移动边界问题的模拟，即，泰勒-库埃特流、静止流体中的振荡圆柱体、椭圆柱体的沉降和球体的沉降。结果表明，该方法具有一阶空间精度，并与其他数值和实验结果有很好的一致性。此外，我们讨论了本方法的两个问题，即，穿透和寄生振荡的本地力，并为他们可能的补救措施。
We propose an immersed boundary-lattice Boltzmann method using the discontinuity of the stress tensor. In the immersed boundary method, the body force which is applied to enforce the no-slip boundary condition is equivalent to the discontinuity of the stress tensor across the boundary. In the proposed method, the boundary is expressed by Lagrangian points independently of the background lattice points, and the discontinuity of the stress tensor is calculated on these points from desired particle distribution functions which satisfy the no-slip boundary condition based on the bounce-back scheme. By using this method, we can obtain the force locally acting on the boundary from the stress tensor of one side of the fluids divided by the boundary, and there is no need to consider the internal mass effect in calculating the total force and torque acting on the boundary. To our best knowledge, the present method is the first one which enables us to calculate the stress tensor on the boundary in the class of the diffusive interface method. In order to validate the present method, we apply it to simulations of typical moving-boundary problems, i.e., a Taylor–Couette flow, an oscillating circular cylinder in a stationary fluid, the sedimentation of an elliptical cylinder, and the sedimentation of a sphere. As a result, the present method has the first-order spatial accuracy and has a good agreement with other numerical and experimental results. In addition, we discuss two problems of the present method, i.e., penetration and spurious oscillation of local force, and a possible remedy for them.