Turbulence Model Sensitivity for Parachute-Like Bodies: A RANS Comparison

Abstract

This paper investigates the sensitivity of computational solutions for flow over hemispherical shell geometries using different Reynolds-Averaged Navier-Stokes (RANS) turbulence models. The study aims to compare the performance of the Spalart-Allmaras (SA) and Shear-Stress Transport (SST) turbulence models on a simplified parachute test case, motivated by challenges in the stability of parachute systems in aerospace applications, such as the Orion Multi-Purpose Crew Vehicle. Using the OVERFLOW CFD solver, a hemispherical shell grid was developed to reduce computational complexity and analyze the model’s impact on flow characteristics. Both models demonstrated nearly identical convergence histories and flow profiles, with minor differences attributed to grid coarseness and floatingpoint errors. Results indicate that the overall computational outcomes are largely independent of the chosen turbulence model for the specific grid and case. Future work will involve grid refinement and 6-DoF simulations to further explore the turbulence model’s effects on dynamic forces.