| Abstrakt: |
High fidelity modeling and simulations methods need to be anchored to data collected from selected flight tests or experiments to develop robust, accurate and validated supersonic flow-simulation methods to predict the behavior of flowfield throughout the wide range flight regimes including highly rarefied supersonic gas flows. We have developed a unified flow model for compressible flows (called RNS model), based on the Generalized Hydrodynamic Equations (GHE) by Alexeev (1994), derived from generalized Boltzmann transport equation. 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, including high Reynolds numbers flows with thin boundary layers, demonstrating good agreement with experimental data, Fedoseyev (2012). Simulations of compressible supersonic flows is a very challenging problem as such flows 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 shock wave (bow shock) is detached from the vehicle at high altitude, and near boundary slip-flow is typical for such regimes. First results for this model has been reported in Fedoseyev (2020). In this paper we provide a comparison of simulation results of our model (called RNS, the Regularized Navier-Stokes) with the experimental data for rarefied hypersonic flows by Allegre et al. (1997). Simulations by DSMC method are also provided for comparison, the DSMC results obtained using the open source SPARTA DSMC code. The comparisons show good agreements of both RNS and DSMC with the experiment, and proove that SPARTA DSMC results can be used as a good approximation for experimental data, in cases where those are not available. [ABSTRACT FROM AUTHOR] |
