MEASUREMENTS OF THE FLOW STRUCTURE AND TURBULENCE WITHIN A SHIP BOW WAVE

Particle image velocimetry measurements around a 7-m-long ship model focus on the flow within the attached liquid sheet, upstream of the point at which the bow wave separates from the model. Performed in a towing basin at a Reynolds number of 1.6×107 and a Froude number of 0.30 (both based on ship length L), these measurements expand upon previous work by examining the bow wave flow at a higher Reynolds number than before. Further, the increased scale of the model and the flow allows finer observation of the flow structure. Individual vector maps show a growing region of negative vorticity originating at the toe of the wave. This shear layer, which first appears at X/L=0.0619, penetrates further into the wave as X/L increases but curves upward to remain close to the forward face. Positive vorticity appears on the top of the wave and at the ship boundary. Repeated runs at X/L=0.0690 produce mean flow and turbulent stress data for this three-dimensional spilling wave. Normal and shear Reynolds stresses are ...