Rotor Airload and Acoustics Prediction Based on CFD/CSD Coupling Method

An advanced airload and noise prediction method based on computational fluid dynamics/computational structural dynamics(CFD/CSD)coupling for helicopter rotor has been developed in this paper.In the present method,Navier-Stokes equation is applied as the governing equation,and a moving overset grid system is generated in order to account for the blade motions in rotation,flapping and pitching.The blade structural analysis is based on 14-DOF Euler beam model,and the finite element discretization is conducted on Hamilton′s variational principle and moderate deflection theory.Aerodynamic noise is calculated by Farassat 1 Aformula derived from FW-H equation.Using the developed method,numerical example of UH-60 Ais performed for aeroelastic loads calculation in a low-speed forward flight,and the calculated results are compared with both those from isolated CFD method and available experimental data.Then,rotor noise is emphatically calculated by CFD/CSD coupling method and compared with the isolated CFD method.The results show that the aerodynamic loads calculated from CFD/CSD method are more satisfactory than those from isolated CFD method,and the exclusion of blade structural deformation in rotor noise calculation may cause inaccurate results in low-speed forward flight state.