Scours in harbour area caused by Voith-Schneider-Propellers


For the propulsion of a ship, propellers accelerate the surrounding water, a propeller jet is created. At low water depths, this propeller jet can hit the bottom. Loose bottom material, such as sand, is eroded when the critical bottom shear stress is exceeded, causing a scour to form. In harbors, scour can lead to impairment of the stability of quays. 

In contrast to conventional screw propellers, there have been no studies to date on scour development by Voith-Schneider propellers (VSP). VSP differ from screw propellers in particular in their vertical axis of rotation. In addition, the amount and direction of the generated thrust can be changed very quickly due to the adjustable pitch of the propeller blades relative to the flow. 

In the Eros-VSP project, knowledge of the VSP-induced flow field is to be expanded, and bottom stresses and changes quantified. An approach developed at the Leichtweiß-Institut für Wasserbau (LWI) to determine the temporal evolution of screw propeller scour is to be modified for Voith-Schneider propellers.

Laboratory tests (LWI TU BS, Voith), field measurements (LWI TU BS) and numerical investigations (FDS TU HH) will be carried out to achieve the objectives.

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