Abstract
In order to get a better understanding of the so called bow-wave-breaking phenomenon occurring on full-bodied hull forms, attempts were made to observe the flow field around the bow of ship models. By use of dye particles injected into the fluid, it was verified that there exists a shear layer beneath the free surface in front of the moving body. Then it was found that the shear layer leads to the formation of necklace vortices spiraling around the bow of the full form even at extremely slow speeds without any visible breaking waves. At higher speeds there appears a visible wave breaking accompanied by intensive vortical motion beneath the free surface. The intensity of the shear layer and the necklace vortices around bluff bows thus seems to have a significant effect on the formation of breaking bow waves.
