Departmental Papers (EES)

Document Type

Journal Article

Date of this Version

6-2006

Publication Source

Journal of Geophysical Research: Earth Surface

Volume

110

Issue

F2

Start Page

F02014

DOI

10.1029/2004JF000126

Abstract

Results are presented examining the interaction between two sandy bed forms under low–sediment transport conditions in a small laboratory flume. The initial artificially made bed forms were out of equilibrium with the flow field. Temporal evolution of bed forms was monitored using time-lapse photography in order to characterize bed form adjustment to the imposed flow. Velocity measurements were collected using an acoustic Doppler velocimeter to characterize both mean flow and turbulence associated with different bed form geometries. Sandy bed forms all had identical initial geometries; however, the initial distance between bed form crests was varied between experiments. Overall deformation of the bed varied as a function of initial bed form spacing; however, bed forms evolved unpredictably as periods of relatively slow change were punctuated by periods of rapidly changing geometry. Subtle changes in bed form trough geometry were found to have a strong influence on turbulence and therefore sediment transport. Comparison with field studies suggests that the mechanisms described herein are active in natural systems.

Copyright/Permission Statement

Copyright © 2005 by the American Geophysical Union.

Keywords

bed forms, turbulence, morphodynamics

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Date Posted: 11 November 2016

This document has been peer reviewed.