An overset generalised minimal residual method for the multi-solver paradigm

Abstract

ABSTRACTThe multi-mesh, multi-solver paradigm makes use of multiple Computational Fluid Dynamics (CFD) solvers in a single overset framework. A framework-level implementation of the Generalised Minimal Residual algorithm applied to the full implicit overset system is presented. The method requires only minimal changes to existing, Python-wrapped CFD solvers and demonstrates improved convergence compared to traditional methods. Preliminary validation for the method is performed using the Poisson equation on two overset grids. The multi-body, overset GMRES method is shown to be equivalent to a conventional implementation which allocates memory for data across all overset grids on a single processor. Results are shown for two time-accurate flow simulations. The first case analyses convergence of a 2D inviscid wedge and the second analyses convergence of a laminar 3D sphere. Both the wedge and sphere bodies shed unsteady structures into nested, background Cartesian grids. In both unsteady cases, the presented overset GMRES method demonstrates superior convergence over traditional methods.