UNCLASSIFIED 



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READ INSTRUCTIONS 

 BEFORE COMPLETING FORM 



1. REPORT NUMBER 



TP 78-5 



2. GOVT ACCESSION NO. 



3. RECIPIENT'S CATALOG NUMBER 



4. TITLE (and Subtitle) 



SAND RIPPLE GROWTH IN AN OSCILLATORY- FLOW 

 WATER TUNNEL 



5. TYPE OF REPORT & PERIOD COVERED 



Technical Paper 



6. PERFORMING ORG. REPORT NUMBER 



7. AUTHORfs; 



Karl E. B. Lofquist 



8. CONTRACT OR GRANT NUMBERffiJ 



CERC Agreement No. 76-30 



9. PERFORMING ORGANIZATION NAME AND ADDRESS 



National Bureau of Standards 

 National Engineering Laboratory- 

 Washington, DC 20234 



D31193 



It. CONTROLLING OFFICE NAME AND ADDRESS 



Department of the Army 



Coastal Engineering Research Center (CERRE-CP) 



Kingman Building, Fort Belvoir, Virginia 22060 



12. REPORT DATE 



August 1978 



13- NUMBER OF PAGES 

 100 



M. MONITORING AGENCY NAME « ADDRESSf/f dlitereni horn Controlling Ot(ice) 



IS. SECURITY CLASS, (of this report) 



UNCLASSIFIED 



16. DISTRIBUTION STATEMENT (of this Report) 



Approved for public release, distribution unlimited. 



.17. DISTRIBUTION STATEMENT (of the abstract entered In Block 20, If different from Report) 



18. SUPPLEMENTARY NOTES 



19. KEY WORDS (Continue < 



aaary and Identify by block t 



nber) 



Coastal processes 

 Equilibrium bed forms 

 Oscillatory flow 

 Ripple growth 



Ripple profiles 



Sand motion initiation 



Three-dimensional bed forms 



Waves 



2Q. ABSTRACT (Vaatinum aa reveram s{«fi> ff rtexrnaeaey aad Identify by block number) 



The development of sand ripples in an oscillatory-flow water tunnel was 

 observed in 104 laboratory experiments approximating conditions at the seabed 

 under steady progressive surface waves. The period, T, and amplitude, a, of the 

 water motion were varied over wide ranges. Three quartz sands were used, with 

 mean grain diameters, D = 0.55, 0.21, and 0.18 millimeter. In 24 experiments, 

 with the bed initially leveled, T was reduced until ripples appeared, and their 

 development to final equilibrium form was observed without further change in T. 



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