Assessment of an Inviscid Euler-Adjoint Solver for Prediction of Aerodynamic Characteristics of the NASA HL-20 Lifting Body

摘要

An Adjoint-based Euler solver is used to calculate the flow on NASA's HL-20 lifting body configuration. The study covers a full Mach range from low subsonic (M=0.3) to hypersonic (up to M=20). Longitudinal and lateral aerodynamic coefficients are calculated. Convergence behavior of the solver is discussed with emphasis on the impact of the HL-20 base flow in subsonic and transonic Mach numbers. Hypersonic flow cases are then studied in detail, with incidence reaching 50 degrees. Computational considerations pertaining to hypersonic flow and the impact of modifying the specific heat ratio are discussed. Representative numerical flow visualizations are included for each flow regime and flow features are discussed. Computational results show good agreement with wind-tunnel data and a second computational method. The study demonstrates the conceptual and preliminary design power of the current Euler-Adjoint solver when applied to complex reentry geometries across their full flight Mach range.