Experimental investigation of noise radiation from a circular plate covered by polyurethane foam

An experimental investigation of the noise reduction achieved by covering a thin circular plate is reported. The plate boundary was unconstrained. One side of the plate was covered by sound-absorbing material so that noise radiation from the other side for different configurations of foam cover was measured and compared with the noise level obtained without any foam cover. It has been shown that substantial noise reduction can be achieved if a specific foam cover is used.