Findings in Aero-Acoustic Simulations for Optimizations

Abstract

The methods of the aero-acoustic optimization toolchain developed by DLR within the VicToria project are further analyzed. From previous investigations, it was settled that an unsteady panel code with a free-wake model poses a fast alternative to higher-order CFD simulations to predict blade-vortex interaction noise. In this paper, a brief validation of both methods against the HART II rotor is done. Design parametric studies with UPM are carried out for which single CFD simulations are placed to examine the correlation between both methods. In the end, an optimization with the panel code as well as CFD is conducted to see how good the final designs match. From this research it is observed that UPM captures plausible trends when altering the chord distribution, but is unable to replicate CFD results for more advance rotor designs based on blade sweep or an-/dihedral. In order to improve UPM for rotor design, it is recommended to additionally model viscosity and generalize the vortex roll-up model further.