« = M^ n^ 'lli7-%hY^ ^^ ' ^3^ ,^,,. (56) 



Here the dimensionless quantity B2(p)> which takes into account 

 the effect of dissipation, is given by 



B (p, = 8;^ iM-f!!! . (57, 



Case B ; The growth of waves at limited fetches as a function of 

 the fetch x. 

 Similarly as in Case A equations (53) lead to the following 

 expressions 



r2„2 ^ „3 



^- = ^^- %,(p)gB,(p) ^^> p^l/3 



(58a) 



and 



^-^i- "'^^ 'iiw-Xh')' ^ '^ ■' ^/2<^*^ • < 



58b) 



These equations have to be evaluated by numerical integration. 



The most important quantity in these equations on which the 

 evaluation of the wave development depends, is the difference C(p) - 

 B(p). In this paper, a first attempt is made to estimate this dif- 

 ference which is determined by the energy supply by wind and the 

 energy losses by virtual friction. At present such an estimate 

 seems possible only with the aid of empirical relationships. It is 

 to be expected that these relationships will be improved in the 

 future as a result of more comprehensive observations, and that theo- 

 retical knowledge will increase especially with regard to the problem 

 of turbulence. The state of the sea and of turbulence in the upper 

 layers of the ocean are seemingly closely related, and the problem 



78 



