Currently, new aircraft called Advanced Air Mobility, such as eVTOL, are being developed. These aircraft are expected to fly at lower altitudes than passenger aircraft. This airspace has traditionally been used by helicopters and other aircraft, raising concerns about noise exposure in urban areas. The number of flights by these rotor aircraft is expected to increase in the future, making it necessary to consider the impact of noise. However, it is difficult to apply existing segment noise calculation methods for fixed-wing aircraft. Therefore, a calculation model was constructed to calculate the noise of these rotorcraft. In this calculation model, the rotorcraft is regarded as a point source with a three-dimensional hemispherical sound source directivity, and the noise at the receiving point can be calculated from the three-dimensional position of the aircraft and the rotor power every 0.5 s. Furthermore, to verify the model's validity, helicopter noise was measured and compared with the model's calculation results for single noise events.
Nakazawa et al. (Wed,) studied this question.