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Examination of a simple approach to wave forecasting, based on dimen- 

 sional analysis, leads to the conclusion that wind-generated waves in the 

 laboratory cannot be expected to have the same form as prototype waves 

 unless they correspond to equivalent scaled fetches. Very low windspeeds 

 must be used to produce waves that are anywhere near fully developed in a 

 laboratory facility of moderate length. The resulting waves are too small to 

 be of much value in testing designs. 



An examination of the microscale procedures, now believed to be re- 

 sponsible for wave growth and of some secondary flow characteristics of wind 

 tunnels, indicates that the relative importance of the mechanisms for wave 

 generation in wind channels is very different from that in unconfined air- 

 spaces. 



Modeling the effects of nearshore wind in modifying waves generated far 

 from shore may be possible if the waveform, as it exists at a modest distance 

 from shore, can be modeled by a mechanical wave generator. If modeling the 

 offshore wave is possible, direct mechanical generation of the desired form 

 may be easier and more economical than adding a wind tunnel above the wave 

 channel. 



Laboratory wind-wave research facilities can be useful for basic research 

 concerning air-sea interaction even though they are of doubtful value in 

 testing engineering designs. 



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