NUMERICAL ANALYSIS OF HIGH-SPEED IMPULSIVE (HSI) NOISE OF PZL W3-A “SOKÓŁ” (FALCON) HELICOPTER MAIN ROTOR IN FORWARD FLIGHT

Abstract

The paper presents the results of a numerical simulation of the flow and acoustic field generated by the PZL W3-A “Sokół” (Falcon) helicopter main rotor in high-speed forward flight conditions based on the URANS approach and the chimera overlapping grids technique. A refined CFD model (40+ million of control volumes, 600+ blocks chimera mesh) was designed to resolve the flow-field together with the low-frequency content of the acoustic pressure spectrum in the near-field of the rotor blades to allow high-speed impulsive (HSI) noise prediction. Detailed 3D data was recorded for one rotor revolution (approx. 3 TB) allowing exceptional insight into the physical mechanisms initiating the occurrence and development of the HSI noise phenomenon.