The Hub Effect on a Propeller Scour around a Pile

Abstract

Propeller induced scour has been taken big attention in last three decades. Erosion caused by propeller jets around berting structures has been an important research subject in engineering area for years. In this study, the hub effect on a propeller scour around a pile was searched. The experiments were performed in a laboratory flume in Yıldız Technical University, Hydraulics and Coastal Engineering Laboratory. A 1/1.5 slope with coarse gravel and rip-rap layer with fine gravel were considered. Pile was constructed at the toe of the slope. Firstly experiments were performed for free propeller jet and then for hub jet. The propeller has 0.1 m diameter and the hub has 0.104 m diameter and 0.3 m length. The experiments were conducted for 560 rpm, 690 rpm and 820 rpm. The results of free and hub propeller jet were compared and it is found that hub causes decrease in scour.