SPH Simulations of Ship Propeller Induced Harbour Bed Erosion

The paper reports on the predictive prospects of Smoothed-Particle-Hydrodynamics (SPH) for simulations of ship propeller induced scours in harbours. Such erosions represent unpleasant phenomena, especially if they occur close to quay walls, and generate cost intensive counter measures. These measures are usually based on a rather weak background knowledge. SPH simulations can help to analyse the erosional processes and to understand the interaction between ship, water, soil and structure. In the present research, a body-force propulsor model based on the open water characteristics is used to represent the ship’s propeller. The evolution of the liquid and granular phase particles is obtained from an SPH-integration of the continuity and momentum equations. The fluid is considered to be Newtonian and the viscosity of the soil-phase is modelled in line with the Mohr-Coulomb yield stress criterion. Water and soil particles interacting in a suspension layer are assigned to a viscosity that is derived from a Chézy-relation between the shear stress and the local flow velocity. A variable particle resolution strategy is applied to handle large domains, in which the areas around the ship hull demand a fine resolution. A complex full-scale application example included refers to the starting sequence of a container ship propeller.