both fetch and duration are to be taken into accoxint, and often the 

 increase of wind-speed with time has also to be considered. It is 

 possible to give numerical solutions for the case of a variable wind 

 V = v(x,t), but this report shall be confined to evaluations of the 

 two special cases considered in the preceding sections, which may 

 give some help in wave forecasting. An attempt to consider more 

 complicated weather conditions at sea for practical wave forecasts 

 will be made in a following report. 



For the j)urpose of numerical evaluation, the derived differential 

 relations are written in non-dimensional form using the "fetch para- 

 meter" gx/v , and gt/v as the "duration parameter." Integrations 

 must be carried out numerically. 



Case A ; Growth of the s ea over an unlimited fetch a s a 

 function of wind duration t. 



1) 



2) 



^ = ^ 12.2p2 ^Y' ^y^p ^ p ; ?< 1/3 (81) 



V 



.2 .-2rp 



^ = ^ '^'^' pJ/3 ' oli,7\i,?^ ^ ^ ^ h ^ ^/3.<P^^ (82) 



° ^2^M -^ 6(1)^M(8 )exp[(r/n)(l-Pj^)6(l)] 

 p 'v^ 



p(l) 5 0^6(1)^5(1)^^ ; (83) 



The "factors of energy supply " C^(p), C^ip) and C^(p) are 

 given by (20), (28) and (30), "the factors of energy dissipation" 



96 



