Comparison of real gas simulations using different numerical methods

Abstract

Two different numerical simulation codes (the SPLIT/NE code and the PoliTo code) are examined in this paper by comparing results for non-equilibrium flow cases using two different geometries, a hemisphere-cylinder-flare (axisymmetric) and a hyperbola-flare-cylinder configuration (axisymmetric and 2-D plane). The solution methods implemented in the codes are essentially different (finite difference, bow shock fitting, matrix splitting and Runge-Kutta high accuracy schemes for SPLIT/NE and finite volume, shock capturing, flux difference splitting and E.N.O. high accuracy schemes for PoliTo). The flow simulations are done employing physical models of different complexity (inviscid and viscous flows, chemically reacting flows in vibrational equilibrium and non-equilibrium, steady and unsteady flows). Comparing the solutions for the different codes, a very good agreement is obtained for both the hemisphere-cylinder-flare flow and the 2-D plane hyperbola-flare-cylinder flow. For relatively small flare angles, this is also true for the axisymmetric hyperbola-flare-cylinder flow; however, for larger flare angles, differences in the solutions can be detected which can be addressed to the formation of a strong recirculation bubble behind the detached flare shock.