Shear Instability of Longshore Currents: Effects of Dissipation and Non-Linearity
- 11 August 1995
- proceedings article
- Published by American Society of Civil Engineers (ASCE)
Abstract
The effect of bottom friction and turbulent lateral mixing on shear instability of the longshore current is investigated. Transition conditions for this instability as a function of non-dimensional parameters related to the basic current, topography, bottom friction and lateral mixing are found. A direct nonlinear numerical simulation of shear instability is presented. The basic flow is found to be supercritical and the amplitude of shear waves can reach at least 20% of the basic flow. A small increase in the period due to non-linearity is also found. Preliminary results suggest that far from criticality there is an important contribution of the instability to the mean flow. Some applications to field and laboratory experiments are discussed.Keywords
This publication has 4 references indexed in Scilit:
- Numerical simulation of vorticity waves in the nearshoreJournal of Geophysical Research: Oceans, 1994
- Edge waves on a longshore shear flowPhysics of Fluids A: Fluid Dynamics, 1992
- Shear instability of longshore currents: A numerical studyJournal of Geophysical Research: Oceans, 1992
- Shear instabilities of the mean longshore current: 1. TheoryJournal of Geophysical Research: Oceans, 1989