Measurements of Real Gas Effects on Regions of Laminar Shock Wave/Boundary Layer Interaction in Hypervelocity Flows for “Blind’ Code Validation Studies

Abstract

Detailed surface heat transfer and pressure measurements have been made in laminar separated regions of shock wave/boundary layer interaction in high-enthalpy flows over double cone and hollow cylinder/flare configurations to provide data sets with well-defined boundary conditions for comparison with Navier-Stokes computations including the effects of nonequilibrium air chemistry. In these experimental studies, which were conducted in the LENS I and XX shock/expansion tunnels, measurements were made in air, nitrogen, and oxygen for a range of Reynolds number conditions at velocities from 8,000 to 22,000 ft/s to provide measurements with which to evaluate the models of real gas chemistry employed in Navier-Stokes codes. Flowfield measurements have been made with high-speed Schlieren photography and interferometry to provide additional measurements to define the size and structure of the separated interaction region. Details of the model configurations and the freestream conditions at which these studies have been conducted, together with earlier measurements and measurements upstream of the interaction regions are presented in this paper to enable computations to be performed with both Navier-Stokes and DSMC prediction methods for "blind comparisons" with the experimental data. These comparisons will be presented at an AIAA meeting during the coming year.

Numerical study of bluntness effects on laminar leading edge separation in hypersonic flow

“…US3D is capable of performing perfect gas and real gas simulations and has also been validated over a wide range of geometries (Drayna, Nompelis & Candler 2006; Holden et al. 2013; Candler, Subbareddy & Brock 2014). The code uses parallel processing to improve the computational time and allows both implicit and explicit time integrations to be conducted.…”

“…Simulations in the present study were carried out using a continuum Navier-Stokes solver, US3D, which has been specifically developed at the University of Minnesota for high-speed flows (Nompelis & Candler 2014;Candler et al 2015). US3D is capable of performing perfect gas and real gas simulations and has also been validated over a wide range of geometries (Drayna, Nompelis & Candler 2006;Holden et al 2013;Candler, Subbareddy & Brock 2014). The code uses parallel processing to improve the computational time and allows both implicit and explicit time integrations to be conducted.…”

Thermochemical Nonequilibrium Modeling for Hypersonic Flows Containing Oxygen

“…5 However, flows containing oxygen (both oxygen only and air-like compositions) have not shown good overall agreement. 5,6 It is suspected that nonequilibrium behavior of oxygen is a potentially significant contributer to the discrepancy in the results. Recent postnormal shock results, 7 including the results in this paper, compare with shock tube experimental data from Ibraguimova 30 and show that state-to-state modeling describes nonequilibrium behavior more accurately than the standard two-temperature modeling approach for hypersonic oxygen flows.…”

“…6 The focus of the work presented in this paper is on Run 87. The freestream flow conditions for Run 87 are shown in Table 4 .…”

“…Thus, it is important to establish the capability of CFD simulation to accurately predict the flow field and surface properties for hypersonic flow conditions. Many hypersonic tunnel experiments have been performed at CUBRC, 5,6 specifically utilizing the CUBRC LENS-XX expansion tunnel. Previous comparisons between CFD and experimental data generated under hypersonic conditions at CUBRC have been performed for various flow compositions.…”