Control Method of the Rotor Noise based on Sound Pressure Cancellation

The volume of noise has become a major issue in limiting the range of helicopter applications. This paper employs a method of the actively controlled drag piece to reduce the volume of rotating noise produced by rotor blades. The flow field characteristics of the rotor blades are numerically simulated using a high-precision RANS solver-CLORNS to obtain high-resolution sound source information. The rotor noise is then predicted using the Farassat 1A formulation and the rotor aerodynamic noise prediction method. To validate the method, a common UH-1H arithmetic example is used. The standard approach was used to calculate the rotor noise characteristics, and particular results were obtained by focusing on the influence of each parameter of the drag piece.