Flow simulation using generalized static and dynamic grids

A new approach is presented for a how simulation system using generalized g rids. In a generalized grid, the physical domain of interest is decomposed into cells with an arbitrary number of edges or faces. The grid can be of s tructured, unstructured, or hanging node type or an arbitrary combination o f the types. A cell-face-based data structure is used to store the grid inf ormation, A flow simulation system is developed for generalized grids that can handle static and dynamic grids, The full Navier-Stokes equations, in t he integral form, are taken as the relations that govern the fluid flow. A cell-centered finite volume scheme is developed for solving these governing equations. The numerical flux across the cell faces is evaluated by an upw ind scheme based on Roe's approximate Riemann solver. A higher-order scheme is formulated by utilizing Taylor's series expansion and Green's theorem. Limiter functions are used to preserve monotonocity. The skin-friction coef ficient is used to evaluate the accuracy of the limiter functions. The gene ralized minimal residual method is utilized to solve the sparse linear syst em of equations resulting from the linearization of the flux vectors. The S palart-Allmaras one-equation turbulence model has been implemented for the generalized grids and is used to evaluate the turbulent viscosity For dynam ically moving bodies, the equations of classical mechanics are used to pred ict the trajectory based on the external aerodynamic acid body forces. A va riety of computational examples are presented to demonstrate the wide range of applications, and the results are compared with experimental data whene ver available.