| Résumé | When the propeller blades pass the ice blocks with virtually very little clearance, high blade-load impulses and subsequently high peak loads do occur. This was first observed during a full-scale trial (1984) of MV Robert LeMeur, and later verified by the model tests conducted at NRC/IMD ice tank. A two-dimensional model with time dependence is used to study dominant features of this phenomenon. The hydrodynamic flow over a blade profile is considered to be constricted by an ice block at proximity condition. The numerical results indicate a peak load about 5.78 times that computed for open water. The associated flow phenomena have been studied in detail, and a peculiar pressure hump due to throttling effect of the rear corner of ice block was discovered . The moment ditch appearing in the distribution of pitching moment is caused by this pressure hump. |
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