SECURITY CLASSIFICATION OF THIS PAGE (When Data Bnterad) 



REPORT DOCUMENTATION PAGE 



READ INSTRUCTIONS 

 BEFORE COMPLETING FORM 



1. REPORT NUMBER 



MR 76-5 



2. GOVT ACCESSION NO 



3. RECIPIENT'S CATALOG NUMBER 



4. TITLE (and Subtitle) 



REFLECTION AND TRANSMISSION CHARACTERISTICS OF 

 POROUS RUBBLE-MOUND BREAKWATERS 



5. TYPE OF REPORT & PERIOD COVERED 



Miscellaneous Report 



^. PERFORMING ORG. REPORT NUMBER 



7. AUTHORfs; 



Ole Secher Madsen 

 Stanley M. White 



8. CONTRACT OR GRANT NUMBERfs) 



DACW72-74-C-000I 



PERFORMING ORGANIZATION NAME AND ADDRESS 



Department of Civil Engineering 

 Massachusetts Institute of Technology 

 Cambridge, Massachusetts 02159 



E31230 



11. CONTROLLING OFFICE NAME AND ADDRESS 



Department of the Army 



Coastal Engineering Research Center (CERRE-SP) 



Kingman Building, Fort Belvoir. VA 22060 



REPORT DATE 



March 1976 



NUMBER OF PAGES 



14 MONITORING AGENCY NAME a ADDRESSf/f d//ferenl from Controlling Ollice) 



15. SECURITY CLASS, (ol this report) 



UNCLASSIFIED 



16. DISTRIBUTION STATEMENT (ol thia Report) 



.Approved for public release; distribution limited. 



17. DISTRIBUTION STATEMENT (ol the abstract 



ed In Block 20, If dlllerent horn Report) 



18. SUPPLEMENTARY NOTES 



19. KEY WORDS (Co 



Breakwaters 

 Energy dissipation 

 Empirical relationships 

 Wave reflection 



sary and Identity by block number) 



Friction factor Reflection coefficient 

 Hydraulics Rubble-mound breakwater 

 Porous material Transmission coefficient 

 Wave transmission 



20. ABSTRACT (Conltnu 



aide If neceeaary and Identify by block number) 



This report presents the results of a study of the reflection and trans- 

 mission characteristics of porous rubble-mound breakwaters. An attempt was 

 made at making the procedures entirely self-contained by introducing empirical 

 relationships for the hydraulic characteristics of the porous material and by 

 establishing experimentally an empirical relationship for the friction factor 

 that expresses energy dissipation on the seaward slope of a breakwater. 



DD 



1473 



EDITION OF I NOV 6S IS OBSOLETE 



SECURITY CLASSIFICATtOM OF THIS PAGE (When Data Entered) 



