ORIGIN OF SUBMARINE DUNES

Resumen

The turbulent bursting process is outlined and attention is drawn to the fact that the "coherence distance" of the regenerating macroturbulent eddies is of a magnitude that is much the same as the length of dunes. Consequently it is postulated that the length of dunes is merely the "imprint" of the coherence distance on the deformable surface of a movable bed and the origin of dunes is explained accordingly. It is shown that the frequently observed similarity between tidal and unidirectional dunes is due to the similarity of the tidal transport and the transport corresponding to an intermittent unidirectional flow. The explanations presented herein are expected to be valid for dunes caused by both unidirectional flows and tidal currents.