Studies in frictionally damped waves. December 1973.

Abstract

Surface waves subject to linear frictional force originating from horizontal bottom stresses. Wave properties for this model are deduced. Theoretical refelction and transmission coefficients were found for these waves when incident to a depth discontinuity positioned normal to the wave crests. These results were compared with experimental ones and agreement was generally good, though there was some evidence of extraneous energy losses by turbulence at the discontinuity. A circular shelf model was considered with the theoretical results showing a large reduction in the "Q" of the resonance peaks when compared with the frictionless case. It was also found that, except at the lower frequencies, a large number of overlapping resonance peaks which were out of phase with one another occupied relatively narrow frequency band. Experiments using several frequencies carried out for the circular sill model and the results were in very good agreement with the theoretical ones