Development of rotor noise prediction code based on vortex method and FW-H acoustic analogy for design of low-noise rotor blade

The attributions of the helicopter to take off and land vertically, to hover and fly forward allow it to be used in congested or isolated areas where fixed-wing aircraft would not be able to take off or land. However, limitations of the rotorcraft generally fall into the category of noise. Rotor blade design plays a large role in how this limitation may be mitigated. Designers are always looking for new ways to design more optimum rotor blade. Thus, the objective of this study is to develop a rotor noise prediction code for low-noise rotor blade design which is based on vortex method and FW-H acoustic analogy. The aerodynamic and aeroacoustic validation study under hover and forward flight conditions was conducted to evaluate the accuracy of the noise prediction code. The results have indicated that the in-house nonlinear vortex method (NVLM) and noise prediction codes have a surprisingly good capability to predict aerodynamic and aeroacoustic characteristics of the rotor blade. This in-house code is expected to be helpful in the early stages of designing low-noise rotor blades.