Flexural-gravity wave motion in the presence of shear current: Wave blocking and negative energy waves

Abstract

Flexural-gravity wave propagation under the action of a compressive force and in the presence of flow vorticity is studied under the framework of linear water wave theory. The occurrences of wave blocking which is analogous to the free surface gravity wave propagation against an opposing current as well as light wave propagation in curved space-time near a black hole are shown to exist. Moreover, negative energy waves that are responsible for making the total energy of the fluid flow less than that without the waves are also analyzed. The effects of compressive force, Froude number, and vorticity on the existence of negative energy waves as well as the occurrence of flexural-gravity wave blocking are graphically illustrated. The variation in group velocity for different flow parameters such as the vorticity, the Froude number, and the compressive force is analyzed. Time-dependent simulations of the propagation of wave packets are calculated.