Numerical Analysis of Rotor Aeroacousitc Scattering Characteristics Considering Fuselage Aerodynamic Configuration Parameters

Based on the FW-H equations, the CFD method and the time domain equivalent source method (TDSEM), the rotor aeroacousitc scattering characteristics considering the fuselage aerodynamic configuration parameters are calculated and analyzed. First, a set of CFD/FW-H/TDESM hybrid analysis method for rotor/fuselage aeroacoustic characteristics is developed. The aeroacoustic characteristics of the UH-1H rotor in hover and a point acoustic source nearby a rigid sphere are calculated, and the employed numerical analysis method is validated through comparisons with reference data. Then, the aeroacoustic characteristics of the Bo-105 in hover (main rotor/fuselage) are analyzed, and the scattered noise is discussed in detail. Finally, the aeroacoustic characteristics of the AH-64 helicopter in forward flight is calculated. In addition, parameters, such as the distance between fuselage and rotor, are quantified, and some conclusions are obtained. The fuselage will influence the directivity of rotor noise, and an appropriate fuselage configuration will reduce the rotor noise at the azimuth of 250-degree(1dB in the present case).