Reduction of Aerodynamic Noise Radiated from Multicopter

The present paper is focused on reducing the aerodynamic noise emitted by multicopter. The effect of the serrations and the dimples of the propeller blades on the aerodynamic noise has been studied experimentally. In addition, we discussed the interaction noise between the propeller and the arm of the multicopter. Multiple peaks were formed in the spectra of SPL. As the distance or height decreased, the peak SPLs and broadband noise increased. The aerodynamic noise was increased when the arm was placed in front of the propeller. We considered the effective countermeasures to reduce the aerodynamic noise emitted by multicopters. The arm located on the downstream side of the propeller is effective in reducing the aerodynamic noise.