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SECURITY CLASSIFICATION OF THIS PAGE 



REPORT DOCUMENTATION PAGE 



form Approved 

 OMB No 0704-0188 

 Exp Date Jun30, 1986 



a REPORT SECURITY CLASSIFICATION 



Unrlaqsi fieri 



1b. RESTRICTIVE MARKINGS 



2a SECURITY CLASSIFICATION AUTHORITY 



2b. DECLASSIFICATION /DOWNGRADING SCHEDULE 



3. DISTRIBUTION /AVAILABILITY OF REPORT 



Approved for public release; distribution 

 unlimited. 



4. PERFORMING ORGANIZATION REPORT NUMBER(S) 

 Technical Report CERC-90-12 



5. MONITORING ORGANIZATION REPORT NUMBER(S) 



6a NAME OF PERFORMING ORGANIZATION 

 USAEWES, Coastal Engineering 

 Research Center 



6b OFFICE SYMBOL 

 (If applicable) 



CEWES-CW-P 



7a. NAME OF MONITORING ORGANIZATION 



6c. ADDRESS (City, State, and ZIP Code) 



3909 Halls Ferry Road 

 Vicksburg. MS 39180-6199 



7b. ADDRESS (City, State, and ZIP Code) 



8a. NAME OF FUNDING /SPONSORING 

 ORGANIZATION 



US Army Corps of Engineers 



8b OFFICE SYMBOL 

 (If applicable) 



9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER 



8c. ADDRESS (City, State, and ZIP Code) 



Washington, DC 20314-1000 



10. SOURCE OF FUNDING NUMBERS 



31672 



1 1 TITLE (Include Security Classification) 

 Laboratory Study on Macro -Features of Wave Breaking over Bars and Artificial Reefs 



12. PERSONAL AUTHOR(S) 



Smith, Ernest R. ; Kraus , Nicholas C, 



13a. TYPE OF REPORT 

 Final report 



13b. TIME COVERED 

 from Sep 87 to Sep 



14 DATE OF REPORT ( Year, Month, Day) 15. PAGE COUNT 

 July 1990 232 



16. SUPPLEMENTARY NOTATION 

 Available from the National Technical Information Service, 5285 Port Royal Road, Springfield, 

 VA 22161. 



17 



COSATI CODES 



FIELD 



GROUP 



SUB-GROUP 



18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number) 

 Breaking waves Wave breaker type Wave plunge distance 



Laboratory study Wave breaker vortex Wave reflection 



Wave breaker index Wave height decay Wave runup 



19. ABSTRACT (Continue on reverse if necessary and identify by block number) 



A laboratory experiment was conducted in a wave tank to examine macroscale features of 

 wave breaking over bars and reefs. Submerged triangular- shaped obstacles representing bars 

 and reefs were installed on a 1/30 concrete slope to cause wave breaking. Seaward and 

 shoreward slopes of the obstacles were varied, as was the deepwater wave steepness H /L , 

 which resulted in 108 monochromatic wave tests and 12 irregular wave tests. Empirical 

 expressions were determined for the wave properties investigated, which included breaker type, 

 height, and depth; plunge, splash, and penetration distance; breaker vortex area; wave decay; 

 wave reflection; and wave runup. Additionally, data acquired from other studies involving 

 plane slopes were reanalyzed to determine breaker indices and plunge distance. Differences 

 were found between wave properties on plane slopes and barred profiles. 



Plunging and collapsing breakers were predominate for regular waves breaking over bars 

 and reefs, whereas spilling breakers occurred on the plane slope. The strength of return flow 



(Continued) 



20. DISTRIBUTION /AVAILABILITY OF ABSTRACT 

 CKuNCLASSIFIED/UNLIMITED □ SAME AS RPT. 



□ DTIC USERS 



22a. NAME OF RESPONSIBLE INDIVIDUAL 



21 ABSTRACT SECURITY CLASSIFICATION 

 Unclassified 



22b TELEPHONE (Include Area Code) 22c OFFICE SYMBOL 



DDFORM 1473, 84 mar 



83 APR edition may be used until exhausted 

 All other editions are obsolete. 



SECURITY CLASSIFICATION OF THIS PAGE 



Unclassified 



MBL/WHOI 



D 0301 0011272 1 



