of the growth of ocean waves under the action of wind probably can- 

 not be solved without considering turbulent energy dissipation. 



Special difficulties are encountered at present when the ear- 

 liest stages of wave development are considered. Here the initial 

 waves which form as wavelets or ripples at very weak winds are not 

 meant, but rather the small, steep, turbulent waves which are gen- 

 erated by stronger winds from short fetches or wind gusts, and which 

 grow rapidly with increasing fetch or duration of wind action. These 

 stages of wave development are to be described by "wave ages" p of 

 about 0.1 to 0.2, that is very "young sea." Our knowledge of the 

 exact empirical relationship 6 = f(p) for p<l/3 is still very weak, 

 and when dealing with equation (l8) it was pointed out that the 

 assumption S = const represents only a first approximation. 



The dimensionless quantities C(p) and B(p) are represented in 

 Fig. 14 as functions of p. Because of the different empirical re- 

 lationships for p<l/3 and p > l/3 and the assumptions at the earliest 

 stages of wave development, a discontinuous change results at p=l/3. 

 In nature, we have to expect a certain continuity in slope of the 

 steepness 6 when p increases above the value I/3. It would have 

 been possible to establish another empirical relationship for p < l/3 

 to approach a more continuous change between p = 0.2 and p = 0.4, 

 perhaps as indicated by the broken line in figure 12, but such at- 

 temps would not contribute to a better understanding of the mechan- 

 ism of wave generation. Therefore it seems to be more expedient 

 to wait for more complete empirical knowledge. For the practical 

 aim in question, it seems adequate to smooth the niiraerical values 

 by assuming a continuous change over p = 1/3 • The smoothing is 



79 



