Prediction of aircraft surface noise during maneuvering flight

Abstract

Research is carried out on the prediction of aircraft surface noise during flight with high maneuverability and high overload. The dual hybrid Reynolds-averaged Navier-Stokes/large eddy simulation (RANS/LES) calculation model based on zonal mixing and turbulent scale mixing is modified, and the new hybrid model is established to simulate complex separated flow accurately. A calculation method for simultaneously calculating aerodynamic/motion, internal/external flow, and compressible/incompressible flow is employed. The dual hybrid RANS/LES model combined with six-degree-of-freedom motion equations is used to simulate the maneuvering process of the aircraft and calculate the surface acoustic load. The calculation results reveal that the acoustic load at the inlet of the engine and tail nozzle is large. During positive overload flight, the surface noise is greater than negative overload due to the stronger turbulent fluctuation on the aircraft surface and the impact of jet noise at the tail nozzle. The contribution rate of jet noise to the overall sound pressure level (OASPL) of the fuselage gradually increased from front to rear. In the maneuvering state, the vortex motion on the aircraft surface is enhanced, and the pressure fluctuation is stronger than that in the cruise state, which makes the surface acoustic load greater than that in the cruise state.