Analytical identification of blade-vortex interaction noise controller suited for miniature trailing edge effectors

The present work focuses on the BVI noise annoyance occurring during helicopter descent flights, and a control methodology suitable for Micro-Trailing Edge Effectors has been presented. The control device actuation aims at generating aerodynamic BVI counter-actions and the low-power requirement make the Micro-Trailing Edge Effectors particulary suited for this kind of high-frequency applications. The controller is set by observing the BVI scenario, and efficiently synthetized through an analytical process based on the Theodorsen theory. The validation process of the proposed control methodology is carried on through numerical investigations of realistic helicopter main rotor in descent flight by exploiting computational tools based on Boundary Element Method and Farassat 1A formulation for the aerodynamic and aeroacoustic solutions, respectively. Since using potential-flow solvers Micro-Trailing Edge Effectors are replaced by trailing edge plain flaps which provide equivalent aerodynamic responses. Preliminary results concerning controller capability to alleviate BVI loads and associated emitted noise are presented and discussed.