Longshore current generation by obliquely incident internal waves

Abstract

It is shown that a significant longshore current of maximum amplitude v = (3 × 10^4/v ) cm sec^?1 (for typical oceanic values) can be forced between the breaker zone and shore by internal gravity waves obliquely incident on a plane beach. In the mean longshore momentum balance Reynolds stress terms appear which can be calculated to O (α), α being a bottom slope parameter, using a WKB approach. With appropriate assumptions being made about the amplitude behaviour of the motion after breaking, the divergence of these stresses does not vanish and forces a current whose magnitude is determined by a balance with viscous stresses derived from vertical eddy motions.