Propeller Wash on a Slope

Erosion protection for quay structures has big importance due to propeller jet damage. Because of economic reasons a great number of large ships can berth with their own power today. During berthing and unberthing, propeller jet may cause serious scour on sloping rip rap banks, around pile or quay walls. Thus, occurrence of ship propeller-induced damages has became very common problem nowadays. In this research, propeller wash on a slope was studied. The experiments were performed in a laboratory flume in Yıldız Technical University, Hydraulic and Coastal Engineering Laboratory. Two different slope angles which were m=2.5 and m=3 were considered. The propeller has 0.1 m diameter and 625 rpm, 690 rpm and 820 rpm in the experiments. The velocity distrubition and scour on the slope were obtained. The propeller jet velocity distrubution was obtained with Acoustic Doppler Velocimeter (ADV) along the propeller axis. The damaged slope profile and the scour and accummulation behaviour at the toe along the spanwise direction were obtained.