Experimental study on scouring of coarse sand and fine sand seabed caused by propeller washing in front of solid wharf

Abstract

This paper presents the results of continuous scouring and intermittent scouring tests on two kinds of seabed soils (d50=0.7mm coarse sand and d50=0.162mm fine sand) induced by propeller washing at the front of the solid wharf. Three propellers with diameters of 70 mm, 130 mm and 150 mm were used for the test. The test results show that under the same test conditions, the maximum scouring depth of the coarse sand seabed is 8.2% to 58% deeper than that of the fine sand seabed under continuous test or intermittent scouring; compared with continuous scouring, intermittent scouring The maximum scouring depth increase caused by the coarse sand seabed is 2% to 4.8%, while it is increased to 5.1% to 37% for the fine sand seabed. The prediction formula of the maximum equilibrium scouring depth on the fine sand seabed caused by the front edge of the solid wharf during the intermittent washing of the propeller is established. This formula is a dimensionless formula, which can be applied to the intermittent scouring of the actual propeller wash.