Surface waves over a convex impedance ground

Abstract

Laboratory experiments are reported for the study of surface waves above a convex impedance surface. Monopole, horizontal dipole, and vertical dipole sources are used in these experiments. The model ground surface is an open-meshed rubber mat with a hole size of 22-mm square and 12-mm depth. The rubber mat is then laid on a rigid masonite curved surface. There are generally good agreements between measurements and predictions based on the residue series theory. In an earlier theoretical study [see J. Acoust. Soc. Am. 89, 107–114 (1991)], Raspet et al. have identified the contribution due to the surface wave poles. However, the present experimental results have suggested that the surface wave pole contributions not only contain the surface waves but also include the creeping waves. The experimental results also show that there are two groups of waves, which are well separated, arriving at different times. The earlier group of waves may be attributed to the creeping waves, while the later group of waves is identified as the surface waves. [Work supported by EPSRC and an Open University Studentship.]