Propeller Scour around an Open Berth Quay

Yee-Meng Chiew, Mao-Xing Wei

Thursday 2 july 2015

16:15 - 16:30h at Mississippi (level 1)

Themes: (T) Sediment management and morphodynamics, (ST) Morphodynamics of estuaries and coastal areas

Parallel session: 13A. Sediment - Coast

The aim of this study is to investigate the temporal and spatial development of the scour hole induced by a confined propeller jet in the presence of an armored slope and vertical skirting in an open berth quay. A series of laboratory experiments was carried out under different test conditions with a range of horizontal distance from the propeller face to the toe of the quay slope, namely, the toe clearance. The scour depth along its center-line was measured at pre-determined time intervals and the overall scour hole profile measured at the end of each test when the asymptotic state was reached. The temporal development of the maximum scour depth is discussed. The asymptotic scour profiles are compared with that induced by an unconfined propeller jet in the absence of any berthing structure. The results show that evolution of the scour hole is significantly influenced by the toe clearance. Moreover, contrary to results obtained from tests associated with an unconfined propeller, the present data reveal that the thalweg of the confined scour hole is not necessarily coincident with the central axis of the propeller. A relationship that describes the location and magnitude of the maximum asymptotic scour depth in terms of the toe clearance, which may be used in the design of quay structures and bed protection, is also proposed.