High-fidelity simulation of the interaction between the wake of a descent capsule and a supersonic parachute

Abstract. The objective of the project is to analyze the unsteady dynamics of the parachute-capsule system in a supersonic airflow while descending during planetary entry. Currently, a combination of Large-Eddy Simulation and an Immersed-Boundary Method is being utilized to examine the evolving flow of a rigid supersonic parachute trailing behind a reentry capsule as it descends through the atmosphere of Mars. The flow is simulated at 𝑀𝑎 = 2 and 𝑅𝑒 = 106. A massive GPU parallelization is employed to allow a very high fidelity solution of the multiscale turbulent structures present in the flow that characterize its dynamics. We show how strong unsteady dynamics are induced by the interaction of the wake turbulent structures and the bow shock which forms in front of the supersonic decelerator. This unsteady phenomenon called ‘breathing instability’ is strictly related to the ingestion of turbulence by the parachute’s canopy and is responsible of drag variations and structure oscillations observed during previous missions and experimental campaigns. A tentative one-dimensional model of the flow time-evolving dynamics inside the canopy is proposed.