Generation of longshore currents by waves and variations in breaker height off Madras

Abstract

Longshore currents may be generated within the nearshore zone either by waves approaching obliquely to the shoreline or by onshore variations in the breaker height, or by combinations thereof. In this paper, large variations in breaker height observed along the coast are studied in relation to longshore currents. The waves approaching the coast from northeast and east-northeast produce southerly longshore currents downcoast while the waves from southeast and east-southeast produce northerly currents upcoast. The magnitude of the currents along the coast are however variable and depend on the distribution of the breaker heights, refraction functions, and the breaker angles along the coast. The computations reveal that no feeder currents are produced in this region