Table 7. Steepness (6), phase velocity ((T). and 

 amplitude of horizontal velocity 

 component u at the sea siirface for three 

 characteristic waves. 



V m/sec 5 10 l6 20 24 28 



8^-wave' 



(d 0.083 0.067 0.0555 0.049 0.0445 0.0407 



0- m/sec .284 7. 00 12.95 17.6 22.6 27.9 



m 



lu m/sec 



p(l)-wave ftT (1) m/sec 5 

 6(1)=0.0406\uq m/sec 



P-* -wave fT „ m/sec 



6„ =0.0222lu m/sec 

 m o- 



velocity of v = I6 ra/sec, for example, the sum of u^ for the p^^^-wave 

 and the §(l)-wave would be 4.31 m/sec. 



When the crests of the B -waves break, zhe waves lose energy 

 and diminish in height. Part of this energy is dissipated and lost 

 with respect to wave motion. But it seems reasonable to assume that 

 another part of the energy, given off by the p -wave will be trans- 

 ferred to the underlying long wave. Because these breakers always 

 occur at the crests of the long waves where the particle displace- 

 mem; is in the direction of wind and wave propagation, the particle 

 velocity originally connected with long wave motion will be speeded 

 up by the forward rushing water masses of the breakers.* Here the 

 breakers do a net amount of work analogous to the work done by the 

 wind in the case of waves with <r < v. The degenerated p -wave becomes 

 regenerated by energy supply from wind, and in this way energy may 



*It also seems possible that the wind will do a net amount of work 

 directly on the long wave, by accelerating the spraying water 

 masses of breakers at the crests and the upper windward slope 

 of the long waves. 



89 



