Novel Methods For Mesh Technology In Flow Field Simulation And Fluid-Solid Interaction Study

Flow field simulation is an essential premise of the flow movement study with the Computational Fluid Dynamics (CFD). Fluid-Solid Interaction (FSI) is an interdiscipline branch of Hydromechanics and Solid mechanics. As an important way to study the interaction between the flow domain and solid domain, Numerical simulation of Fluid-Solid Interaction is drawing more and more attention now. Mesh technology is one of the key problems in flow field simulation and the fluid-solid interaction solution. Mesh quality, adaptability and computational efficiency are very important factors in successfully constituting and solving the FSI modeling. Some key problems of mesh technology in numerical simulation of fluid-solid interaction were researched in this dissertation.With a large number of documents and materials, a comprehensive summarize about mesh generation, update technology was presented. Then, based on the family of mapping functions, structured mesh system for 2D/3D flow field was generated. In order to adapt to the changes of field function density in the practical studies, the interpolation formula which can control the mesh density was derived, and then the mesh modeling for the air flow field by these formula was constituted to verify the effectiveness of the present interpolation formula. Moreover, a new technique was proposed to improve the quality of mesh modeling in both circular domain and cylindrical domain by introducing the embedded block, and the minimum angle distribution of the mesh system based on the present technique was statistically analyzed and some comparison with the result by other method was made, in order to verify the improvement. With the program based on the present method, the flow fields of two space structures were meshed. It is confirmed that this method has a good adaption to the structures with complicated shapes and the calculation with the mesh system generated by the method is valid. Though the comparison between different mesh models, it was indicated that the use of variable density mesh model can greatly improve the efficiency of mesh generation and the iterative calculation with a high-precision simulation.For the motion of the flow field mesh, a novel update method based on the mapping structured mesh was presented, by using mapping interpolation function to calculate the displacement of the flow field mesh node and adding it on the original mesh node coordinate to get the new mesh of flow field. Through the mesh update computation for flow fields of two dimension square structure, spindle structure and the cubic structure, it showed that the present method can keep the original topology and has a fast computation for mesh update and higher mesh quality.Furthermore, the constrained counterforce distribution technique and the projection interpolation method were proposed to exchange the computational data from flow field to solid field and reverse respectively. Finally, with a series of computation, it was revealed that the better effect of data transmission between the interface of flow filed and structural field was reached.