Breaking of gravity waves in the motion of a vertical plate in a two-layer liquid

Results of experimental studies of surface and internal waves generated by translational motion of a vertical plate covering the entire cross section of the channel are discussed. It is found that the waves do not break at the critical propagation speeds predicted by the linear theory or the first approximation of shallow water theory. Breaking begins only at higher propagation speeds, at which the stabilizing effect of wave dispersion ceases. Quantitative information is given that can be used to test mathematical models and numerical methods.