Flow Visualization around a Dune

Abstract

The study of the formation and migration of sand dunes has a long history, but a sound understanding of the turbulent mechanisms behind dune has proved elusive. In this paper, in order to reveal the detailed vortical structures behind a three-dimensional dune, PIV measurements were performed in a circulating water channel with a constant free-stream velocity of 0.2 m/s. Instantaneous and time-averaged velocity distribution in the side and top planes were obtained and the complex reverse flow and eddies behind the dune were examined.