非结构动网格在三维可动边界问题中的应用

研究用于非结构动网格的弹簧近似方法，采用顶点弹簧描述，导出并讨论了弹簧倔强系数的取值。通过引入边界修正和扭转效应修正，对标准弹簧近似方法进行了改进，转动翼型算例的结果表明，改进后的方法大大提高了网格变形能力和网格质量，应用该动网格方法耦合求解基于（Arbitrary Lagrangian-Eulerian,ALE）描述的三维Euler方程，模拟了作俯抑振动的矩形机翼绕流，计算结果与实验数据及文献计算结果十分一致，作为多个自由刚与流体耦合运动问题的简单例证，耦合刚体动力学方程，模拟了激波与双立方体的相互作用，得到了非定常流场结构，研究表明，基于弹簧近似的非结构动网格与有限体积流式流场解算器相结合，是模拟包含运动边界的非定常流动问题的有效方法。

DYNAMIC UNSTRUCTURED GRID METHOD WITH APPLICATIONS TO 3D UNSTEADY FLOWS INVOLVING MOVING BOUNDARIES

Spring analogy method for dynamic unstructured grids is studied. The stiffness of the springs in the modified vertex spring analogy is analyzed. Improvements considering torsional spring effect and boundary effect are developed to standard method. Application of the improved spring analogy method to rotating airfoil grids shows that the new method greatly improves the deforming ability and the quality of the mesh. This dynamic grid method coupled with 3-D ALE Euler solver is then applied to simulate unsteady transonic flow about an oscillating rigid rectangular wing. Computational results are in good agreement with experimental data and that of other literature. To demonstrate the capability in solving interaction problems of multiple rigid body and fluid, the whole methodology coupled with rigid body dynamics equations is used to simulate propagating shock and double cube interaction, time-dependent flow structures are obtained. It can be concluded from the research that the improved spring analogy method coupled with the unsteady finite volume solver developed in this paper, is an effective way to study fluid and structure interaction problems with small boundary displacement.