The experimental investigation of nominal wake of ice-going ship attached with ice based on SPIV technology

Abstract

This paper is based on 76000DWT Panmax Bulker with Ice Class 1B, By using PIV measuring technology and towing DANTEC PIV system, the nominal wake field in open water is measured. Bilge vortex, propeller cap vortex and hook-shaped velocity contour are all observed precisely. The results show that the flow field characteristics are in accordance with stern flow field of U-huge ship, such as KVLCC and JBC. Then the stern nominal flow field is measured as the ship is attached to ice. Axial velocity distribution, velocity vector distribution and streamline are also analyzed. The results indicate that attachment of ice load makes the stern region produce dummy thickness which is equal to the thickness of ice. The dummy thickness destroys the fine linetype design and makes the stern become V-type which is not the best stern type. The attachment of ice in the bottom and side shell lead to the disturbtion stern nominal flow field has to bear when naked hull is sailing. Turbulent boundary layer around the shell is destroyed. Non-streamlined shape of ice produces complex vortex, and the disturbtion among vortexes results in the appearance of disordered vortex structure.