DETAILED NUMERICAL SIMULATIONS OF A SUPERSONIC INLET-ISOLATOR

Abstract

An isolator is an important component of dual-mode scramjet engines that separates the combustor from the engine inlet. This flow section contains a time-varying shock-train that adapts to external variations in order to provide a stable flow to the combustion chamber. The goal of this study is to understand the key modeling issues in comput-ing the flow inside an isolator. We develop a large-eddy simulation (LES) based computational tool using a conser-vative finite difference method. This tool is validated using detailed measurements from an experimental isolator. Sev-eral different models, numerical schemes, and computational grids are tested. The shock structure inside the isolator is relatively stable and insensitive to the computational details. All the simulations overpredict the velocity fluctuations in the boundary layer. Further, simulations exhibit boundary layer separation due to shock impingement, a feature ab-sent in the experiments. These studies indicate that current LES modeling practices are inadequate for describing isola-tor physics.