Wave radiation stress

There are differences in the literature concerning the vertically dependent equations that couple currents and waves. In this paper, currents are purposely omitted until the end. Isolating waves from currents allows one to focus on two main topics: an explanation of Stokes drift with apparent mean vorticity obtained from an otherwise irrotational flow and the determination of vertically dependent wave radiation stress which, when vertically integrated, conforms to that obtained by Longuet-Higgins and Stewart ( 1964 ) and Phillips ( 1977 ) nearly 50 years ago and, more recently, by Smith ( 2006 ). Discussion begins with the simple case of nonlinear flow beneath a stationary wavy wall.