Strategies for CFD Investigation and Optimization of the External Aerodynamics of a Sounding Rocket

Abstract

Historically, aerodynamics has always played a leading role in the design process of space launchers and rockets. Mission and flight performances during the atmospheric flight phase strongly depend on the vehicle’s response to the external airflow characteristics. The study of the aerodynamics of sounding rockets, in particular, can take advantage of a few aspects: among others, their smaller size, compared to the proportions of conventional space launchers, allows them to be studied while substantially reducing computational costs in numerical simulations and maintaining the possibility of scaling the results. In this work, we propose a multi-objective optimization workflow through CFD investigation of the aerodynamic performance of a sounding rocket. More specifically, the final objective of the process involves optimizing aerodynamic drag and the stability response to a gust-type disturbance by defining and modeling both issues adequately with objective functions. We divide the optimization process into the following steps: first, we introduce a test case and a preliminary response surface analysis based on semi-analytical results. Then, we set up an ARMOGA-based multi-objective optimization process on the latter metamodels. Subsequently, following a Pareto clustering analysis, we identify a neighborhood of optimal solutions. Finally, we develop a CFD-based optimum refinement using ESTECO modeFRONTIER and Ansys Fluent. At each step, we also evaluate the degrees of freedom an end user could have in defining the optimum for some specific needs. An application of selected optimization techniques to a field case study completes the work.