MEAN-FLOW MEASUREMENTS IN THE BOUNDARY LAYER AND WAKE AND WAVE FIELD OF A SERIES 60 CB=0.6 SHIP MODEL - PART 1: FROUDE NUMBERS 0.16 AND 0.316

Part 1 of this two-part paper presents results from a towing-tank experiment conducted in order to explicate the influence of wavemaking by a surface-piercing body on its boundary layer and wake and provide detailed documentation of the complete flow field appropriate for validating computational methods. Mean-velocity and pressure field measurements were performed for Froude number 0.16 and 0.316 for a 3.048 m Series 60 CB=0.6 hull form at numerous stations from the bow to the stern and into the near wake. For Froude number = 0.316, free-surface effects are very significant, whereas for Froude number = 0.16, they are negligible, except near the bow, such that comparison of the results enables the identification of the salient features of the wave induced effects. Wave profiles and local and global elevations were also measured. In addition, resistance tests were conducted. The experimental equipment and procedures are described and the results are discussed to point out the essential differences between the flows at low and high Froude number. On the forebody, the differences are primarily in the outer (inviscid) flow, except at the bow, whereas on the afterbody and in the near wake, both the inner (inviscid) and outer flows are altered. The results are discussed to assess the nature of the interaction between wavemaking and the boundary layer and wake. Most of the interaction can be explicated as a result of the wave elevations, wave-induced pressure gradients, and the displacement effects of the boundary layer. Part 2 concerns scale effects on near-field wave patterns and comparisons between the experimental results and inviscid theory.