Prediction of hovering rotor noise based on reynolds-averaged navier-stokes simulation

A rearrangement of Navier-Stokes equations by using general-function theory, provides an accurate theoretical model for describing the propagation of noise from a moving surface to the far field. The data surface of the Kirchhoff formulation is fictitious and penetrable, where as its main benefit is that the nonlinear effect is accounted for by performing the integral on the data surface covering the nonlinear flow region. Reynolds-Averaged Navier-Stokes (RANS) equations are used to consider the influence of viscous effect in the near field and get more accurate information about noise sources. These equations model the nonlinear viscous flowfield near the rotor blades. The results of RANS simulation using chimera-grid methodology is validated for the Caradonna and Tung rotor model. The computed acoustic pressure using RANS/FW-H_pds for the UH-1H rotor is compared with experimental data and shows good agreement.