Assessment of HPCMP CREATE-AV Helios for Interactional Aerodynamics of Hub Wakes Impinging on a Horizontal Stabilizer

1 Experimental data from a high Reynolds number Interactional Aerodynamics Experiment (IAE) conducted in the Pennsylvania State University water tunnel of de-featured baseline and low drag helicopter hubs with a horizontal stabilizer downstream is compared with unsteady computational fluid dynamics (CFD) analyses using HPCMP CREATE™-AV Helios. CFD modeling employs a multi-mesh paradigm and Reynolds-Averaged Navier-Stokes (RANS) or Detached Eddy Simulation (DES) turbulence models. Total hub drag is predicted within 5 percent, while peak- to-peak loads, azimuthal variation and frequency content are fairly predicted. The drag reduction of the low drag hub compared to the baseline hub is 30 percent for both experiment and CFD. Lift (download) on the downstream horizontal stabilizer is predicted within 15 percent, a difference most likely attributable to sidewall modeling. Wing lift time histories for both hubs compare poorly with data, and the frequency content is lacking in many instances. The computed phase-averaged time histories of wing lift are investigated for convergence. Notably, DES turbulence modeling showed no significant improvement over more cost-effective RANS. Overall, additional research is needed to confirm the ability of high-fidelity computational tools and hybrid RANS/LES turbulence models to predict quantitative details of long age hub wake interactions on rotorcraft empennages.