Stability Analysis for High-Enthalpy Cone Experiments in HELM and HIEST Facilities

In the present paper, several boundary-layer stability codes are compared, based on hypersonic, high-enthalpy boundary-layer flows around two different blunted cones: a 7 deg and a 10.9 deg half-angle blunted cone. One part of the code-to-code comparison, which is conducted between seven different codes, assesses the influence of different numerical approaches for the second-mode instability. The focus of the paper characterizes the role of the high-temperature gas effects on the second mode. The experimental test cases for the comparison are provided by two high-enthalpy wind-tunnel facilities: the High Enthalpy Shock Tunnel (HIEST) of Japan Aerospace Exploration Agency (JAXA) and the High-Enthalpy Laboratory Munich (HELM) of the University of Bundeswehr Munich. Analyses between the various computational stability codes and experimental measurements are performed, quantifying the high-temperature gas effects and the influence of uncertainties (e.g., small mean-flow or wall-temperature variations). A comparison between air and [Formula: see text] test gases is also performed.