Upwind unstructured scheme for three-dimensional combusting flows

As an interim step towards the development of a hybrid upwind structured/unstructured solver for combusting/multiphase flowfields, the TRI3D unstructured code of Barth has been extended to analyze multicomponent combusting flows. The extensions mimic the Roe/total variation diminishing (TVD) based thermochemical extensions in the structured solver, CRAFT, and entail a strong coupling of chemical species equations and complete linearization of the chemical source term, treated in a fully implicit manner. Issues regarding the quality of solutions obtained using focally one-dimensional Riemann flux procedures and TVD limiters are more pronounced In unstructured formulations and are dealt with in depth in this article. Comparative studies of structured and unstructured analyses of laminar premixed flames, ducted shock-induced combustion, and blunt-body shock-induced combustion serve to delineate these issues and the need for solution adaptive gridding and improved flux limiters to capture flame zones properly.