Enhanced RBF mesh deformation method and multi-body trajectory simulation

Multi-body separation is a kind of common mechanical problem which exists widely in the field of Aeronautics and Astronautics. Because of its complexity, studying this kind of problems is very difficult either using flight or wind tunnel test. Therefore, the establishment of an unified, efficient and accurate numerical method for simulating multi-body separation has great application value. In multi-body trajectory simulation, computational grids need to accurately depict the large magnitude of relative motion among all solid boundaries. The ideal approach is using a single set of mesh, without adding or deleting the grid nodes or changing the original grid topology, just through mesh deformation to depict the relative movement. On the basis of radial basis function (RBF) mesh deformation technology, the intelligent Laplacian smoothing algorithm is introduced, which greatly improve the ability of pure RBF mesh deformation technology to avoid quality decreasing and topology damaging, and successfully simulate the process of multi-body separation. The flow solver includes four types of grid cell, which respectively are tetrahedron, triangular prism, hexahedron and pyramid. A new unified mesh quality assessment standard is presented as the execute criterion of intelligent Laplacian smoothing. This mesh deformation and smoothing technology is fully integrated into Navier-Stokes equations and 6-DOF moving equations to validate its feasibility by a typical store separation problem. The computational results are compared with experimental data, which demonstrate the accuracy and ability of presented method in dealing with the large magnitude of relative motion among multiple moving boundaries.