基于浸入边界-谱元法的流体柔性体耦合运动研究

Numerical simulation of fluid flexible body interaction based on immersed boundary-spectral element method

为了模拟大变形柔性体与黏性流体耦合运动的动力学行为,该文发展了一套基于浸入边界-谱元法的数值模拟方法。该数值方法中,流体运动在欧拉坐标下采用谱元法模拟,柔性体运动在拉格朗日坐标系采用有限差分法求解,两者的耦合通过浸入边界法实现。首先对低雷诺数方柱绕流后柔性悬臂梁流固耦合振动问题进行数值模拟,并将计算结果与其它文献计算结果进行比较,验证了该耦合计算方法的可靠性。然后研究了高雷诺数下方柱绕流后柔性悬臂梁流固耦合振动情况,得到柔性结构的耦合振动特性和流场动态分布特征。该文的数值方法放宽了由大拉伸系数引起的稳定性限制,能更灵活地被运用于复杂柔性边界条件的情况,为后续对各种柔性体流体耦合的研究提供了基础。

In order to simulate the dynamic behavior of the coupled motion of a large deformed flexible body and a viscous fluid,a numerical simulation method based on the immersed boundary-spectral method is developed.The fluid motion is simulated by the spectral element method in Euler coordinates,and the flexible body motion is solved by the finite difference method in the Lagrangian coordinate system.The coupling between the two is realized by the immersion boundary method.The fluid-solid coupling vibration problem of flexible cantilever beam after the square column flow around with low Reynolds number is numerically simulated.The calculation results are compared with other literatures to verify the reliability of the coupling calculation method.At the same time,the fluid-solid coupling vibration of the flexible cantilever beam after the column flow around with the high Reynolds number is studied,and the coupled vibration characteristics of the flexible structure and dynamic distribution characteristics of the flow field are obtained.The numerical method in this paper relaxes the stability limitation caused by the large tensile coefficient,and can be applied more flexibly to the complex flexible boundary conditions,which provides a basis for the subsequent study of fluid coupling of various flexible bodies.