Roll torque modeling of an hypersonic reentry vehicle : Numerical analysis of cross-hatching phenomenon

摘要

During atmospheric reentry, hypersonic vehicles encounter extreme aerothermal solicitations. In order to absorb those substantial heat quantities, re-entry bodies are covered with an ablative thermal protections systems. This strong interaction between the re-entry body and the flowfield entails vehicle surface geometry modification that potentially generates non axisymetric shapes which may create lateral force and roll torque. This research focuses on understanding the roll torque effects induced by ablation patterns and propose a method to quantify it. Specifically for the cross-hatching patterns, which occurs in the form of diamond shaped roughness created by the interaction between the hypersonic boundary layer and the ablative material. To gain more insights on these aerodynamic effects, an extensive use of numerical tools and modelling methods have been made. After a short description of the cross hatching phenomenon, a three dimensional vehicle geometry with parametric roughness is presented. In order to optimize the computational costs and explore a broad range of roughness configurations, a numerical design of experiments using Latin Hypercube Sampling had been used. Finally a meta model of the roll torque coefficient as a function of the cross-hatching parameters and the flowfield conditions is generated.