Exploring the Accuracy of CFD Predictions for the Wake of a Hypersonic Inflatable Aerodynamic Decelerator

Hypersonic Inflatable Aerodynamic Decelerators (HIADs) present unique challenges that require accurate predictions of complex wake physics. This paper presents a comparative study between wind tunnel experiments and CFD simulations to investigate the wake velocities behind a simplified HIAD model at Mach 10. The CFD simulations were performed using unstructured meshes to capture the complex structure of both the wake and the flow around the sting. The experiments utilized planar laser-induced florescence (PLIF) to measure the off-body wake velocities in a non-intrusive manner. Modeling the turbulent fluctuations with steady Reynolds-averaged Navier-Stokes (RANS) models yielded large errors in wake velocities. Delayed Detached-Eddy Simulation (DDES) more accurately predicts the wake velocities near the body and captured the same trends as experiments with increasing Reynolds number. However, DDES had difficulty predicting the shear layers near separation, underpredicting the shear layer thickness. The sensitivity of the hybrid RANS/LES results to the mesh resolution are also demonstrated.