| Abstrakt: |
Simulations need to be validated by experiments to develop robust, accurate hypersonic flow-simulation methods to predict the wide range of flight regimes including highly rarefied hypersonic gas flows. We have developed and used a unified flow model for compressible flows (called RNS), based on the Generalized Hydrodynamic Equations (GHE) by Alexeev (1994), derived from generalized Boltzmann transport equation (GBE). The model is supposed to account for kinetic effects (intermediate Knudsen number, fluctuations) in the continuum approximation. This model has been explored for simulations of incompressible viscous flows for a wide range of problems and flow parameters, demonstrating good agreement with experimental data, Fedoseyev (2012). Simulations of hypersonic flows is a very challenging problem as those can exhibit both continuum and non continuum flow regimes. Typically, the flow can be continuous to transitional in the near field flow structure, and free molecular flow in the far field. The bow shock can be detached from the vehicle at high-altitude, and near boundary slip-flow is typical for such regimes. First results of RNS model for hypersonic flows have been reported in Fedoseyev (2020), Fedoseyev and Griaznov (2021). In this paper we continue a comparison of simulation results of our RNS model with the experimental data for rarefied hypersonic flows by Allegre et al (1997) and several other works. Simulations by Direct Simulation Monte Carlo (DSMC) method are provided for comparisons. The comparisons show good agreements of both RNS and DSMC with the experiment, or each other, confirming that RNS model can be used for simulation of hypersonic rarefied flows. [ABSTRACT FROM AUTHOR] |
