stage of a study or early in the phase I planning stage) with the model is 

 needed to help determine the cause of a problem to aid in directing future 

 field, laboratory, or numerical investigations required to obtain a viable 

 engineering solution to the problem. 



The principal value of the System 21 Mark 8 model is the combination of 

 refraction and diffraction, providing improved wave calculations relative to 

 refraction models which are more widely used. There are hydrodynamic processes 

 the model cannot handle, but it is more sophisticated than most other short 

 wave numerical wave codes available. It is also well documented and should be 

 considered a helpful addition to the other numerical and laboratory tools 

 available for use in analyzing coastal engineering problems. 



IV. SUMMARY 



This report has discussed the range of application of the short wave DHI 

 System 21 Mark 8 model for various wave conditions and depths. The general 

 steps used in applying the model are presented, along with an example of the 

 wave transformation, which simultaneously included refraction, diffraction, 

 shoaling, and reflection. 



Possible uses of the System 21 Mark 8 model in the short wave mode are: 

 the study of wave transformation near small harbors, shore-connected or 

 offshore breakwaters, inlets, or in shallow areas of complicated bathymetry. 

 Use of the model for short waves in areas larger than 1 square mile (2590 

 square kilometers) for normal wave periods is not usually cost effective. In 

 these cases, a combination of models, where one model treats the large-scale 

 area and another treats the small-scale area, would be more appropriate. 



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