Effect of Interactional Aerodynamics on Computational Aeroacoustics of Sikorsky's Notional X2 Platform

Abstract

An in-house acoustics code, ACUM, was used in conjunction with full vehicle CFD/CSD coupling to create a computational aeroacoustic framework to investigate the effect of aerodynamic interactions on the acoustic prediction of a compound coaxial helicopter. The full vehicle CFD/CSD was accomplished by using a high- fidelity computational fluid dynamics framework, HPCMP CREATETM-AV Helios, combined with an in-house computational structural dynamics solver to simulate the helicopter in steady forward flight. A notional X2TD helicopter consisting of a coaxial rotor, airframe, and pusher propeller was used and split into three simulation cases: isolated coaxial and propeller, airframe and full helicopter configuration to investigate each component’s effect on the others noise as well as the total noise. The primary impact on the acoustic prediction was the inclusion of the airframe in the CFD simulation as it affected both coaxial rotors as well as the propeller. It was found that the propeller and coaxial rotors had a negligible impact on each other.