PLIF- Velocity-measurements and computations of a hypersonic wake flow field

Abstract

A hypersonic shock-tunnel flow around a generic model of a planetary entry probe is analyzed. Planar laser-induced fluorescence is applied to measure the velocity and the rotational temperature everywhere in the flow field. The experimental test case is compared to simulations performed with the direct simulation Monte Carlo (DSMC) method. Effects of rarefaction are observable in the wake, and the simulations characterize the flow as chemically frozen. However, it is shown by comparison of the results with both thermal nonequilibrium and equilibrium simulations that strong coupling exists between thermal relaxation processes and flow field parameters. The agreement between simulations and measurements is good, except in the far wake close to the centerline, where unsteady behavior of the experimental flow indicates the onset of turbulence, which is not modeled by the DSMC simulation. Show more