Reduction of turbulent boundary layer induced interior noise through active impedance control

Abstract

The use of a single actuator tuned to an optimum impedance to control the sound power radiated from a turbulent boundary layer (TBL) excited aircraft panel into the aircraft interior is examined. An approach to calculating the optimum impedance is defined and the limitations on the reduction in radiated power by a single actuator tuned to that impedance are examined. It is shown that there are too many degrees of freedom in the TBL and in the radiation modes of the panel to allow a single actuator to control the radiated power. However, if the panel modes are lightly damped and well separated in frequency, significant reductions are possible. The implementation of a controller that presents a desired impedance to a structure is demonstrated in a laboratory experiment, in which the structure is a mass. The performance of such a controller on an aircraft panel is shown to be effective, if the actuator impedance is similar to but not the same as the desired impedance, provided the panel resonances are well separated in frequency and lightly damped.

Experimental validation of virtual absorbed energy of piezoelectric patch actuators in decentralized velocity feedback control of a plate

“…However, the physical information of the structure and its sound radiation generally cannot be acquired conveniently. Therefore, several researchers focused on this problem and proposed some other cost functions [4][5][6][7] to find the optimal feedback gain instead of minimizing the kinetic energy, such as maximizing the energy absorption of actuators [6,7].…”

“…Decentralized velocity feedback control for a smart structure has been investigated by many authors [1][2][3][4][5][6][7]. Control gain is a key factor in decentralized velocity feedback control, which determines the performance and stability of the control system directly.…”

Investigation of sound transmission through a finite length cylindrical shell in the presence of an exterior turbulent boundary layer

“…In the following, Maury et al(2002c).characterized the case of sound transmission through a flat double-panel, representative of an aircraft sidewall excited by a TBL. Remington and Curtis (2008) examined a single actuator tuned to an optimum impedance to control the sound power radiated from a TBL excited aircraft panel into the aircraft interior.…”