Wave-Induced Eddies and "Lift" Forces on Circular Cylinders 



Neided ring 



Moving bulkhead 

 wave generator 



12-inch pipe line- ^ 



Wave gage on platform 

 Wave gage on side 

 of tank 



— Still water level 



Wave gage on side of tank 

 -»— Wave gage on platform 

 — 3' sensitive section 



Dummy piles used in some tests 



fl 



It 



-Rubber sieve 

 Gap 



Stop 



Arm to support sensitive 

 section of 12" pipe 

 Hole in 10" pipe for arm 



— Bending arm 

 SR-4 Stigin gage 



— Diaphragm 



10" pipe 



-0.25" 



— 12" pipe 



(a) DIAGRAM OF WAVE TANK 



Section A-A 

 (b) DYNAMOMETER FOR MEASURING WAVE FORCE 



Figure 9. BEB arrangements (Ross, 1959) 



than twice the pile diameter so that the "lift" forces were always 

 substantial compared with the longitudinal forces. Longitudinal and 

 "lift" forces were measured for waves with periods from 3. 75 to 

 16. seconds and heights from 2. 1 to 7. 7 feet. The two sets of 

 data labeled "BEB data, 1972 analysis" in Figure 8 are ratios of 

 forces per unit length of pile, using the average of four consecutive 

 waves for one set, and the maximum of the four waves for the second 

 set. Representative examples of the BEB data are given in Table 3. 



Owing to the manner in which Bidde analyzed and reported his 

 data, it would be expected that they would lie between the maximum 

 and mean values obtained by the writers for the same Nj^q. If this 

 is the case, it appears that Bidde reached the value of Nj^q that 

 divides the regime from a strong dependence of the ratio of lift to 

 longitudinal force upon Nj^q to one in which it is essentially inde- 

 pendent of Nj££. 



Bidde found for the smaller diameter ( 1-— inch) pile that N-d 



777 



