Assessment of Create-AV Helios for Complex Rotating Hub Wakes

Experimental data from high Reynolds number water tunnel experiments conducted at the Pennsylvania State University of a de-featured helicopter hub are compared with unsteady computational fluid dynamics (CFD) analyses using CREATE-AV Helios. CFD hub modeling employs a Spalart-Allmaras Detached Eddy Simulation (SA-DES) model. Different off-body wake treatments (baseline SA-DES, coarse off-body SA-DES, and inviscid) are computed. Total hub drag is predicted within 7%, while peak-to-peak loads, azimuthal variation and frequency content are accurately captured. Drag breakdown and frequency content by component is investigated. Mean and unsteady wake velocity characteristics from PIV and LDV measurements are compared with the calculations. The mean streamwise velocities are over-predicted. The frequency content in the CFD simulations is seen to be stronger and broader than experiment with excessive dissipation from near- to far-wake.