High Enthalpy Differential Equation-Based Estimates for Spherical/Cylindrical Forebody Shock Stand-off Distance

Lawrence Dechant, Ross Wagnild, Kyle Lynch, Sean Kearney, Justin Wagner, Jungyeoul Maeng

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Here we consider the shock stand-off distance for blunt forebodies using a simplified differential-based approach with extensions for high enthalpy dissociative chemistry effects. Following Rasmussen [4], self-similar differential equations valid for spherical and cylindrical geometries that are modified to focus on the shock curvature induced vorticity in the immediate region of the shock are solved to provide a calorically perfect estimate for shock standoff distance that yields good agreement with classical theory. While useful as a limiting case, strong shock (high enthalpy) calorically perfect results required modification to include the effects of dissociative thermo-chemistry. Using a dissociative ideal gas model for dissociative equilibrium behavior combined with shock Hugoniot constraints we solve to provide thermodynamic modifications to the shock density jump thereby sensitizing the simpler result for high enthalpy effects. The resulting estimates are then compared to high enthalpy stand-off data from literature, recent dedicated high speed shock tunnel measurements and multi-temperature partitioned implementation CFD data sets. Generally, the theoretical results derived here compared well with these data sources, suggesting that the current formulation provides an approximate but useful estimate for shock stand-off distance.

Original languageEnglish (US)
Title of host publicationAIAA SciTech Forum and Exposition, 2023
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
ISBN (Print)9781624106996
DOIs
StatePublished - 2023
Externally publishedYes
EventAIAA SciTech Forum and Exposition, 2023 - Orlando, United States
Duration: Jan 23 2023Jan 27 2023

Publication series

NameAIAA SciTech Forum and Exposition, 2023

Conference

ConferenceAIAA SciTech Forum and Exposition, 2023
Country/TerritoryUnited States
CityOrlando
Period1/23/231/27/23

ASJC Scopus subject areas

  • Aerospace Engineering

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