PROPELLER JET FLOW, PILE SUPPORTED PIERS AND SEA BED INTERACTION

Abstract

In maritime trade, from all over the world, transportation performed over the seas has been rapidly increasing due to high technological improvements leading the ships to have huge power and high speeds. The approach of even the big ships to the piers is now done by using the ship’s own engine power without the help of tugs because of the operation and economic reasons. However; this has been observed to cause local scour around the piers. Local scour commonly defined as the scour which is occurred in the immediate vicinity of the hydraulic structures due to the direct impact of the structure on the flow. It is very important to reduce local scour caused by ships propeller jets. A thorough understanding of the erosion of the bed due to local scour remains a challenge since it is associated with a highly turbulent flow field. The propeller jet has 3D flow area and high velocities. The erosion problem around the berthing structures due to propeller jet can occur in three ways. These are; a) On a slope, b) At the bottom of vertical wall, c) Around piles. In this study, propeller jet flow was considered to investigate scour formations around piles with non-cohesive sediment bed. The scour mechanism induced by propeller jet with and without pile conditions were investigated experimentally and their comparisons were made. Because there was not enough study for the scouring process for pile type berthing structures under propeller jet flow in the literature.