Experimental evaluation of active noise control in a thin cylindrical shell

The effect of frequency on the performance of an active control system is examined. The effects are related to the mechanisms of the structural-acoustic coupling and the nature of the control field acoustics. The cylinder used in the experiment consists of a thin aluminum shell terminated with two end plates in a cylindrical configuration. The experiment was conducted at 324, 450, and 475 Hz, corresponding to shell nondimensional frequencies of Omega = 0.15, 0.21, and 0.22. It is found that the nature of the primary field is determined by the coupling between the shell and the acoustic space as well as the frequency of excitation.