APPENDIX B 



TEST WAVE CHARACTERISTICS 



The following discussion concentrates on wave effects in the 96-foot 

 tank, where most of the reported data were obtained. Regular, high waves 

 were desired for the tests, but the mechanically driven piston generated 

 waves with complicated and variable profiles. Wave variability may be 

 either temporal or spatial. Temporal variability in the wave condition 

 at some point can be caused by irregularities in the generating piston 

 motion over a time large compared to T, or by accumulating reflected 

 wave energy. Figure B-1 shows wave records that should reveal any 

 important temporal variability for a steep wave in the 96-foot tank 

 without a test pile. (The test pile was located near G = 25 feet with 

 the second wave gage close to G = 23 feet in most tests.) There was 

 little change in wave condition when the generator had been running for 

 1, 5, or 15 minutes, indicating the gently sloping hogshair beach was 

 effectively absorbing incident wave action. Note that the crest height 

 does decrease slightly in time. 



After 



15 



Minutes 



Figure B-1. Changing wave condition in time after start of 96-foot 

 tank generator. Test conditions: T = 2.32 seconds, 

 d = 1.00 foot, E = 4.0 inches. 



There was appreciable reflection off some of the larger test piles 

 (e.g., the 3x3 H-pile), which resulted in a slight variation in the 

 incident wave recorded by the second wave gage at various pil£ orienta- 

 tions. The incident crest height variation approached (0.05 W) , at most. 

 in any reported test; if the gage away from the pile recorded larger 



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