SEAWAY 



Fig. 4 Streamlines of air flow and total pressure variatian at sec in J madel (frarn Motzfeld, 1937) 



Fig. 5 Same as Fig. 4 but for third model 



3 A trochoidal wave of length height ratio al)out 10 



4 A wa\'e of circular arcs with sharp 120 deg angles at 

 cre.sts and length/height ratio of 7.5, which closely re- 

 sembles the theoretical wave of limiting height. 



The wave profiles and dimensions are shown in Fig. 2, 

 the pressure distribution along the models in Fig. 3, and 



the pressure distribution in the air and streamlines in 

 Figs. 4, 5 and 0. Thickening of the boundary layer and 

 the pha.se lag of the pressure distribution is noticeable on 

 all models, but only on the sharp-crested model No. 4 is 

 separation of the flow observed. The horizontal dy- 

 namic (i.e., due to pressure distribution) drag !!'„ per wave 

 length is obtained by integration 



