利用高精度浸没边界-格子Boltzmann流固耦合格式模拟2维刚体自由沉降运动

自由刚体的流固耦合问题是计算流体动力学领域的热点问题，也是实际工程应用中的常见问题。为了推广最新提出的基于迭代力项的浸没边界-格子Boltzmann(immersed boundary-lattice Boltzmann, IB-LB)耦合格式使之能够计算自由刚体的流固耦合问题，首先在原控制方程中添加自由刚体的运动方程组，然后利用IB-LB耦合格式离散并数值求解该数学模型。以两小球在水箱中的自由沉降运动为例，比较了本方法与其他流固耦合算法的计算结果。最后模拟了富有挑战性的矩形平板在水箱中飘动的过程，捕捉到了与实验数据相吻合的刚体运动轨迹和流态结构，通过对比本法和现有同类算法的单步平均耗时与平板平均速度，证明了推广后算法在计算复杂流固耦合问题上有较高的计算效率和精度。

Appling the highly accurate immersed boundary - lattice Boltzmann coupling scheme to simulate the sedimentation of two dimensional rigid bodies in liquid

The fluid-structure-interaction (FSI) of free rigid bodies is a hot issue in computational fluid dynamics, and is also a common problem in engineering applications. In order to extend the newly proposed iterative force based immersed boundary-lattice Boltzmann (IB-LB) coupling scheme to simulate FSI problems in which free rigid bodies are involved, the equations of motion were firstly added to the governing equations, then the mathematical model was discretized and solved by IB-LB coupling scheme. Using the sedimentation of two particles as an example, the numerical results of present method and other FSI algorithms were compared. Finally, a challenging problem concerning the fluttering of a rectangular plate in a water tank was addressed in the IB-LB framework. The trajectories of the rigid bodies and the flow patterns were in good agreement with existing experimental results. By comparing the execution time per time step and the measured averaged velocities with that of existing FSI algorithms, this method was found to be computational efficient and accurate in simulating complex FSI problems.