Microscopic investigation of Rayleigh-Taylor instability in a sedimenting suspension

通过微观粒子和流体动力学的数值计算，研究了悬浮液中的瑞利-泰勒不稳定性。由于格子Boltzmann方法与浸没边界方法相结合的非常快速和大规模并行机器的可用性，GPU加速了基于粒子的中尺度流体动力学模拟。当我们使用浸入边界格子Boltzmann方法时，我们观察到在固-液界面上的边界滑移，这在悬浮系统的计算中引起显著的误差。为了解决速度滑移问题，我们将双弛豫时间碰撞算子应用到格子Boltzmann方法中，并证明了我们的基于双弛豫时间隐式修正方法的数值方法成功地防止了流动穿透固体表面以及非物理速度滑移。

We investigate Rayleigh-Taylor instability in a sedimenting suspension by the numerical calculation of the microscopic particle and fluid dynamics. Because of the availability of very fast and massively parallel machines of the lattice Boltzmann method combined with the immersed boundary method, the GPU accelerates particle-based mesoscale hydrodynamic simulations. When we use the immersed boundary-lattice Boltzmann method, we observe the boundary slips on the solid-liquid interface that cause the significant error in the computation of the suspension system. In order to solve the velocity slip problem, we apply two relaxation times collision operator to the lattice Boltzmann method, and demonstrate that our numerical method based on the implicit correction method with the two relaxation times succeeds in preventing the flow penetration through the solid surface as well as unphysical velocity slips.