Robert D. Corsaro
Naval Res. Lab., Code 7130, Washington, DC 20375-5350
Surface-mounted sensors can be used to monitor the performance of an underwater acoustic projector, or to control its impedance in a complex dynamic environment. However, there are few examples in the literature of studies of the issues involved in marrying sensors and actuators. These issues include spatial sampling, near field sensing, internal resonances, and both direct and extraneous coupling mechanisms, all of which can contribute to complicate the system transfer functions and limit the applicability of this approach. The work presented here includes measurements made on a 1--3 composite actuator with integrated pressure and velocity sensor layers. Both free-field sensitivities and actuator--sensor coupling transfer functions are evaluated in the NRL Large Pool Facility. These are compared with predictions from simple acoustic models. Implications for local control of the actuator's surface are also discussed.