Local Scour Around Structures in Tidal Flows
Year: 2002
Type: conference-paper
Abstract: An experimental study was carried out to investigate the development of local scour around structures in tidally-reversing flows. Tests were made in a laboratory flume with square, circular and rectangular structures (aspect ratio=2) for a range of water depths and with two sizes of bed sediment. Two types of tidal profile were studied: a square-wave profile with a constant velocity in each direction and a profile in which the velocity was varied sinusoidally so as to be representative of conditions in astronomical tides. Tests were made with a range of different tidal durations and peak velocities. After a sufficient number of cycles, the scour depths at either end of a structure reached an equilibrium value. In most of the tests with clear-water scour, the equilibrium depth was significantly less than the maximum depth that would have been produced by a unidirectional current of the same magnitude. However, in the case of live-bed scour, the equilibrium scour depth was found to be similar to the corresponding unidirectional value. Based on an analysis of the results, a method of predicting the equilibrium scour depth was developed using existing data on unidirectional scour and the ratio between the half-cycle duration of the tide and a characteristic time of the scouring process.
Authors: R.W.P. May, M. Escarameia
Language: English
Subfield: Earth-Surface Processes
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W275198053