Nonharmonic Control of the Blade-Vortex Interaction Noise of Electrically Controlled Rotor

Table 2

Comparison of the effect of flap nonharmonic input on noise control.

Rotor type	Control scheme	Noise peak
ECR - preinstallation angle of 8°	Reference	116.62 dB
	Scheme A	112.77 dB
	Scheme B	113.86 dB
ECR - preinstallation angle of 4°	Reference	113.35 dB
	Scheme C	109.85 dB
	Scheme D	109.6 dB
ECR - preinstallation angle of 6°	Reference	115.52 dB
Conventional rotor	Reference	111.82 dB