Energy leakage from Rayleigh waves on a fluid-loaded, layered half-space

The dispersive energy leakage rate of the zeroth-order leaky Rayleigh mode on a fluid-loaded, layered half-space has been determined experimentally for the first time. Data are presented for a layer of copper on stainless steel and are compared to the prediction of a recent theoretical model. Good agreement with the model calculation is seen in the magnitude of the energy leakage rate, which is related to the lateral displacement of a finite beam, and its dependence on the layer thickness over acoustic wavelength. The rapid variation observed in this rate may be relevant to the design of layer thickness measurements in the acoustic microscope.