The Advanced URANUS Navier-Stokes Code for the Simulation of Nonequilibrium Re-entry Flows

Abstract

In order to predict the thermal and mechanical loads during re-entry, the URANUS (Upwind Relaxation Algorithm for Nonequilibrium Flows of the University of Stuttgart) has been being developed at the Institute of Space Systems (IRS) of the Universität Stuttgart. For the accurate determination of the thermochemical conditions, advanced thermochemical relaxation models for the gas-phase as well as sophisticated gas-surface interaction models have been developed. The Navier-Stokes equations for the 11-component air flow, which consists of N₂, O₂, NO, N, O, N₂⁺, O₂⁺, NO⁺, O⁺, N⁺ and e^-, have been derived by the Chapman-Enskog method from the Boltzmann-Equation. The linearized system of equations is solved fully coupled and fully implicitly, employing Newton's method. In the paper, the modelling is described in some detail and selected simulation results are presented.