Acceleration Effects on Fluid-Sediment Interaction; Final rept. 1 Oct 2005-30 Jun 2008

摘要

The long-term goals of this research are: (i) to identify all relevant physical processes that participate in and contribute significantly to sediment transport in near-shore coastal waters; (ii) to investigate each of the identified processes in order to understand the underlying physics in a quantitative manner; (iii) to develop simple predictive models for each process; and (iv) to incorporate the simple predictive process-models in a predictive model for beach profile response to the action of waves and currents. The objective of the present research is to evaluate the effect of fluid accelerations in near-shore waters. The first part of the research intended to determine the importance of the subsurface sediment transport rate induced by the pressure gradient (acceleration) associated with the passage of the front of a forward-leaning, near-breaking or broken wave. We have concluded that this subsurface transport rate is of small importance compared with the surficial transport rate caused by shear stresses acting on the sediment bed. Consequently, the objective of the second part of the research was to develop and verify the accuracy of an easily applicable methodology to compute surficial transport under near-breaking and breaking waves (hereafter referred to as near-shore waves).