Figure 26 superposes, peak water measurements at the 6-inch circular 

 pile and at the pile with 25 fins, in the side-by-side situation shown 

 in Figure 14. Wave conditions were d = 2.33 feet C71 centimeters), 

 T = 3.55 seconds, E = 4.Q inches (IQ centimeters), G = 18 feet C5.5 

 meters) . The finned pile was tested both with a fin forward and with a 

 channel forward; the channel -forward position gives measurements at 0° , 

 ±14.4°, ...; the fin-forward position gives measurements at ±7.2°, 

 ±21.6°, .... The minimums in each pattern are located near ±120°. How- 

 ever, the pattern for the finned pile has higher, narrower front and 

 rear maximums than the pattern for the smooth pile. This increased 

 articulation is a general feature of the peak water patterns for piles 

 with channels, compared to the patterns for smooth pile's (circular 

 piles and the flat plate) . 



The effects of increasing wave height at T = 2.32 seconds on the 

 [W(B)/W] patterns measured with the flat plate, the 1x2 H-pile, and the 

 2x1 H-pile (with relatively deep channels) are shown in Figure 27. 

 Figure 27(a) shows that the three obstacles have negligible effects for 

 small waves. For each pile, the normalized pattern shows more distinct 

 features as wave height increases. The patterns for the 2x1 H-pile have 

 the most marked features: a front maximum region with a sharp border 

 near 6 = +55°, symmetrically located minimums near B = ±80°, and a broad, 

 relatively high rear maximum. For the 1x2 H-pile, the front maximum 

 region is broader with a less distinct edge, the minimums occurring near 

 g = +115° are slightly deeper, and the rear secondary maximum is more 

 sharply defined but lower than that for the 2x1 H-pile. At the two 

 H-piles, the maximum water level occurs slightly away from g = 0° for 

 the highest wave, due to flow around the leading face and into the front 

 channel. The flat plate gives the smoothest variation of peak water 

 with orientation angle, so the minimums and 'the rear maximum are not well 

 defined. 



Figure 28 shows normalized patterns measured at the same three piles 

 in the highest test waves at two other periods; the features just des- 

 cribed are again apparent. However, at T = 3.10 seconds, the 2x1 H-pile 

 causes a deeper minimum than the 1x2 H-pile. At T = 1.55 seconds, the 

 patterns for the H-piles are skewed rather than symmetric in the front 

 maximum region; there is also a slight depression in the center of the 

 rear maximum for the 2x1 H-pile. 



Figure 29 presents waveforms measured within the 2x1 H-pile for 

 B = 0°, 20°, 40°, and 90°. For B = 90°, the transformed wave has a much 

 broader and lower crest than the incident wave, indicating that peak 

 crest flow bypasses the channel. The other three waveforms are similar 

 to the incident waveform (see App. B, Fig. B-4) , although crest height 

 is increased by runup. 



The various channeled piles were tested primarily to examine the 

 influence of channel geometry on the angular width of the front maximum 

 region in the peak water pattern. Figure 30(a) defines an angle 6 

 describing the pile channel geometry; the streamline sketches in 

 Figure 30(b) indicate how 9 can influence the peak water pattern. 



49 



