Abstract: The article presents two improvements on the spring analogy for unstructured mesh deformation in engineering applications in which large boundary motions are encountered. A gradually updating scheme which generates gradient spring stiffness by the interpolation method on Delaunay graph is proposed to improve the deformation spread. The spring-interpolation approach is proposed to improve the efficiency of the spring ana-logy. The approach first generates a background mesh (coarse mesh) of the solution domain. Then the defor-mation of the background mesh caused by boundary movements is solved by a spring analogy. Finally, the deformation of the computational mesh is obtained by an interpolation method on the background mesh. Examples demonstrate that the presented method significantly improves the deforming ability of meshes as well as the mesh quality after deformation. Additionally, examples also show that the proposed approach improves the efficiency of mesh deformation effectively by reducing the order of the equations of the spring analogy. 

Key words: dynamic meshes, mesh deformation, unstructured mesh, spring analogy, background grid, Delaunay graph