Application of surface conformed linear mesh and data subdivision technique to a spinning projectile

Abstract

In this paper, we report a spinning projectile application of a parallel CFD program featuring surface-conformed isotropic mesh subdivision. The subdivision technique generates finer computational mesh without user interaction using a 3-D hybrid unstructured coarse base. The main motivation behind the subdivision technique is to overcome the bottleneck in generating and processing of the computational meshes with billions of elements. First, we generate a coarse mesh using any unstructured mesh generator. Then, we subdivide the coarse mesh to the level of resolution needed for the simulations. Finally, we conform mesh nodes on solid surfaces to the original geometry since linear subdivision ignores surface curvatures. We use K-D tree search algorithm in the surface mapping. To deform interior mesh nodes due to the surface correction, we use the spring analogy method since deformations are very small. Surface correction is implemented in parallel using the Message Passing Interface. The new mesh obtained from the isotropic subdivision preserves mesh density distribution of the original coarse mesh. The mesh subdivision with surface correction is integral part of our Variable Intensity Computational Environment. A projectile test case with and without spinning at different angles of attack are used to demonstrate the applicability of this method. Flow solutions are obtained using our compressible Navier–Stokes flow solver, CaMEL Aero, with the Detached Eddy Simulation turbulence model. Flow solutions and mesh subdivisions are performed in our parallel cluster at the Jackson State University.