Interaction of surface waves with vorticity in shallow water

Vortical flows in shallow water interact with long surface waves by virtue of the nonlinear terms of the fluid equations. Analytical formulae are derived that quantify the spontaneous generation of such waves by unsteady vorticity as well as the scattering of surface waves by vorticity. In a first Born approximation the radiated surface elevation is linearly related to the Fourier transform of the vorticity. The ``dislocated'' wavefronts that are analogous to the Aharonov-Bohm effect are obtained as a special case.