It is possible that the ratio p * is not strictly constant for 

 all wind velocities. Probably, it is smaller at lower wind speeds, 

 but this question has to be checked by observations. In this con- 

 nection, Chapter I of this report, where this particular question 

 has already been discussed, may be referred to. With very weak winds, 

 a value p = I/3 is to be expected when v = I.23 m/sec. If at a wind 

 velocity v = 1.5 m/sec the value ^^ = 0,38 as given in [8], it fol- 

 lows from equation (60) that ^^ = I.30, The differences are perhaps 

 only of minor significance. 



6) Generation and growth o f longer waves . 



Within the fetch area where the waves are generated there always 

 exists a large number of wave trains with different lengths and 

 heights, traveling with the wind or at small angles to the wind di- 

 rection. Fluctuations of both the wind velocity and direction may 

 thereby contribute to the formation of short crested irregular waves, 

 and it does not seem astonishing that a complicated pattern of ir- 

 regular wave motion results from interference and criss-crossing. 

 But experience shows that special systems of larger waves always can 

 be recognized in the wave mixture . They dominate the sea surface as 

 characteristic waves and are the striking features of the wind driven 

 undulations. 



So far the discussion of wave generation has dealt with waves 



called "sea" or "6 -waves." When these waves have attained a certain 



'^m 



maximum length and height, or a certain "age" ^^ and steepness 6^^^, 

 they apparently do not continue to develop, but remain constant as 

 relatively steep waves, breaking from time to time. However, the 

 complex sea in this stage is not fully developed. If the wind con- 



84 



