Dynamic unstructured grid methodology with application to aero/propulsive flowfields

Abstract

An edge-based, three-dimensional upwind unstructured flow solver with fully coupled finite-rate chemistry is presented for transient aerodynamic and propulsive flowfields with moving and/or deforming boundaries. This viscous flow solver features higher order Roe/TVD numerics where the grid dynamics is integrated with the flux computation. Three different grid methodologies have been investigated for specific classes of problems; a spring analogy method, a solid-body elasticity formulation, and a cell layering technique. The solid-body elasticity method is shown to provide superior results over the spring analogy formulation for problems where boundary surfaces are shearing relative to each other. A significant contribution of this work is the development of a cell layering technique for handling large boundary motion. The cell layering technique embeds/deletes layers of tetrahedral cells as the flow domain expands/shrinks allowing for efficient and accurate flow computations without global remeshing. These methodologies have been demonstrated on practical problems such as multiple body aerodynamics and automotive in-cylinder combustion.