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1. AGENCY USE ONLY fLeavebtanir; 



2. REPORT DATE 



November 1998 



3. REPORT TYPE AND DATES COVERED 



Final report 



TITLE AND SUBTTTLE 



Wave Breaking on a Current at an Idealized Inlet; Coastal Inlets Research 



Program, Inlet Laboratory Investigations 



j6. AirTHOR(S) 



Jane M. Smith, William C. Seabergh, Gordon S. Harkins, Michael J. Briggs 



5. FUNDING NUMBERS 



PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 



U.S. Army Engineer Waterways Experiment Station 

 3909 HaUs Ferry Road, Vicksburg, MS 39180-6199 



8. PERFORMING ORGANIZATION 

 REPORT NUMBER 



Technical Report CHL-98-31 



SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 



U.S. Army Corps of Engineers 

 Washington, DC 20314-1000 



10. SPONSORING/MONITORING 

 AGENCY REPORT NUMBER 



11. SUPPLEMENTARY NOTES 



Available from National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161. 



12a. DISmiBUnOWAVAILABIUTY STATEMENT 



Approved for public release; distribution is unlimited. 



12b. DISTRIBUTION CODE 



3. ABSTRACT (Maximum 200 words) 



Laboratory measurements of wave shoaling and breaking on an ebb current were made in an idealized inlet in a 

 wave basin. The experiment arrangement, procedures, and data analysis are described. The wave and ebb current 

 measurements showed increased shoaling and breaking (compared to no current, shifting of the spectral peak to lower 

 frequencies, and energy dissipation concentrated at the spectral peak and higher frequencies). The measurements were 

 used to evaluate and develop formulations of wave dissipation on a current for application to a spectral wave model. 

 Whitec^ping dissipation formulations underpredicted breaking on a current in shallow water, whereas the bore-based 

 wave dissipation relationship of Battjes and Janssen and a relationship developed in this study provided good estimates 

 of wave-height decay on an ebb current Tables of the wave and current parameters are provided as an ^pendix. 



14. SUBJECT TERMS 



Coastal Inlet 

 Ebb currents 

 Laboratory measurements 



Wave breaking 

 Wave dissipation 



15. NUMBER OF PAGES 



57 



16. PRICE CODE 



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UNCLASSIFIED 



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UNCLASSIFIED 



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20. UMITAT10N OF ABSTRACT 



NSN 7540-01-280-5500 



Standard Form 298 (Rev. 2-89) 



Prescribed by ANSI Std. Z39-18 

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