Modelling and measurement of sand transport processes over full-scale ripples in oscillatory flow

✍ Scribed by Jebbe J. van der Werf; Jan S. Ribberink; Tom O'Donoghue; Jeffrey S. Doucette

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 937 KB
• Volume: 53
• Category: Article
• ISSN: 0378-3839
• DOI: 10.1016/j.coastaleng.2006.02.002

✦ Synopsis

A new series of laboratory experiments was performed in the Aberdeen Oscillatory Flow Tunnel (AOFT) and the Large Oscillating Water Tunnel (LOWT) to investigate time-averaged suspended sand concentrations and transport rates over rippled beds in regular and irregular oscillatory flow. The wave-induced oscillatory near-bed flows were simulated at full-scale. Five series of experiments were carried out. During the two AOFT experimental series, ripple dimensions, ripple migration rates and net sand transport rates were measured under regular and irregular asymmetric flow for two different sand types. The three LOWT experimental series focussed on measurements of the ripple dimensions, ripple migration rates, time-averaged suspended sand concentrations and net sand transport rates under regular asymmetric and irregular weakly asymmetric flow for two different sand types. From analysis of new and other full-scale data, it is concluded that the lower part of the time-and bed-averaged concentration profile (up to two times the ripple height above the ripple crest level) has an exponential profile. A new reference concentration formula is proposed based on the formula of Bosman and Steetzel [Bosman, J.J., Steetzel, H.J., 1986. Time-and bed-averaged concentration under waves. Proc. 20th ICCE Taipei,