Sand bed configurations under 2-d standing waves

Laboratory experiments conducted in a wave basin with movable sand bed have shown that, under the action of 2-D standing water waves, longitudinal sand bars with small ripples riding on their tops are formedbeneath the nodes of standing waves. Wavelengths of the sand bars are approximately equal to one-half of those of standing water waves. The formation of sand bars under standing waves over an initially horizontal sand bedis explained by the suction and impinging effects of the wave action. Amathematical model for describing the induced density of sediment-water mixture due to wave action is proposed. By employing the induced-density modeland mass conservation of sediment-water mixture, a numerical simulationmodel is constructed. Bed configurations resulting from the actions of 2-Dstanding waves are studied by using the simulation model. The simulationresults of sand bed configuration under the action of 2-D standing waves arein good agreement with those obtained from laboratory experiments.