EXPERIMENTAL STUDY ON LOCAL SCOUR AND COUNTERMEASURE AROUND PILE FOUNDATION OF OFFSHORE WINDFARM

Abstract

 The foot protection bag such as Filter Units (FU) is the most common countermeasure for the reduction of the local scour around the monopile of the offshore windfarm facilities. However, it takes a lot of time to set all the FU around the monopile. In this study, collar-type countermeasures were suggested and investigated the reduction of local scour through the movable bed experiments. As an experimental result, the reduction of local scour was not enough only with the collar-type countermeasure. Meanwhile, the reduction of local scour by using both the collar-type countermeasure and FU was enough and almost the same as the reduction of local scour only with FU. As a result of 3D numerical simulation under the fixed bed condition of the experiments, the reason why the reduction of local scour was not enough only with the collar-type countermeasure was the large velocities vicinity of the collar-type countermeasure.