Parallel computation of two-dimensional laminar inert and chemically reactive multi-species gas flows

Abstract: Purpose – A computational fluid dynamics code for the calculation of laminar hypersonic multi-species gas flows in chemical non-equilibrium in axisymmetric or two-dimensional configuration on shared and distributed memory parallel computers is presented and validated. The code is designed to work efficiently in combination with an automatic domain decompositioning method developed to facilitate efficient parallel computations of various flow problems. Design/methodology/approach – The baseline implicit numerical method developed is the lower-upper symmetric Gauss-Seidel scheme, which is combined with a sub-iteration scheme to achieve time-accuracy up to third-order. The spatial discretisation is based on Roe's flux-difference splitting and various non-linear flux limiters maintaining total-variation diminishing properties and up to third-order spatial accuracy in continuous regions of flow. The domain subdivision procedure is designed to work for single- and multi-block domains without being constrained by the block boundaries, and an arbitrary number of processors used for the computation. Findings – The code developed reproduces accurately various types of flows, e.g. flow over a flat plate, diffusive mixing and oscillating shock induced combustion around a projectile fired into premixed gas, and demonstrates close to linear scalability within limits of load imbalance. Research limitations/implications – The cases considered are axisymmetric or two-dimensional, and assume laminar flow. An extension to three-dimensional turbulent flows is left for future work. Originality/value – Results of a parallel computation, utilising a newly developed automatic domain subdivision procedure, for oscillating shock-induced combustion around a projectile and various other cases are presented. The influence of entropy correction in Roe's flux-difference splitting algorithm on diffusive mixing of multi-species flows was examined.