FORMATION OF DUNES BY TIDAL FLOWS

Abstract

Schematical relations for the size of dunes and for the duration of their development are derived assuming that the large scale formations on the surface of a movable bed are due to the largest eddies of turbulence. The considerations are confined to the simplest case of a two-dimensional flow and to the cohesionless granular material. The relations for tidal dunes are obtained by generalising the relations for unidirectional flow dunes, Special cases and the validity regions of the forms presented are discussed; suggestions for future measurements and model tests are included.