propeller-ice interaction; hydrodynamic load; ice blockage; 3-D BEM
A 3-D boundary element method is developed to calculate unsteady hydrodynamic force acting on a marine propeller under the influence of ice blockage at proximity condition. The boundary surfaces are discretized into triangular elements, and on each panel the velocity potential is distributed uniformly. The potential jump on the helical wake surface is determined by applying Kutta condition at trailing edge. A part of influence coefficients are renewed at each time step due to the motion of ice-block. Computed results show that the maximum thrust and torque of propeller can be 1.6 times the normal value when the ice-block reaches the propeller; the local loading at blade section can be about 6 times the normal value. The numerical results provided by the present computer model are useful in the design of propeller for Arctic vessels.