centimeters), T = 3.55 seconds, W = Q.5 foot (15.2 centimeters), and the 

 centers of the two piles are an equal distance from the wave generator 

 (G = 29 feet, '8.8 meters). The white tapes on the two piles extend to 

 the same elevation above the SWL and are located on the face or on the 

 flange directly facing the generator. 



In Figure 14 (a and b) , the crest is approaching, and runup begins 

 in the front channels of the finned pile. In Figure 14(c), runup is 

 occurring on the face of the smooth pile, and a "stairstep" runup is 

 visible in the front channels of the finned pile; this runup has a hori- 

 zontal free surface and differs between neighboring channels. In Figure 

 14(d), a distinct bow wave exists forward of the finned pile, while a 

 higher uprush occurs on the smooth pile's face in a thin sheet; the water 

 surface slope at the side of the smooth pile is about twice as great as 

 the side slope at the finned pile. In Figure 14(e), the crest has passed 

 the piles; the water level forward of the finned pile is dropping and 

 the water sheet on the smooth pile's face is falling. The speckles of 

 light on the water surface behind each pile indicate disordered flow in 

 the wake regions. In Figure 14(f), the runup at the front of each pile 

 has dropped farther, and a splash up the rear of each pile is visible. 

 In Figure 14(g), the crest is far beyond the two piles, and a circular 

 splash is radiating outward from the front face of the smooth pile. 



3. H-File with Deep Channels . 



Figure 15 shows a wave incident directly into the deep channel of 

 the 5x1 H-pile (g = 0°), and Figure 16 shows this pile's flange facing 

 the wave generator, so the visible channel is at B = 90° relative to 

 the wave direction. Test conditions are: d = 2.33 feet, T = 3.55 

 seconds, W = 0.5 foot, 64 frames per second film speed. 



In Figure 15, the elapsed time between successive photos is one- 

 sixteenth second. In Figure 15 (a to f ) , the main wave crest is approach- 

 ing the pile. A secondary crest occurred on the forward face of the 

 main crest. Although barely visible, it caused the noticeable runup in 

 Figure 15(d). In Figure 15(f), the water level in the channel is again 

 the same as the surrounding water level. In Figure 15 (h, i, and j), 

 runup is visible at the pile's web, as the main crest approaches the pile. 

 The water surface has a complicated curvature until it becomes horizontal 

 at its maximum (Fig. 15, k), when the wave crest is at the center of the 

 pile. Slight breaking (aeration) commences at the leading edges of the 

 pile in Figure 15 (k) and spreads toward the generator as the runup falls 

 in Figure 15(1 and m) ; this breaking is apparently associated with flow 

 reflected from the pile jetting out of the channel. In Figure 15(1, m, 

 and n) , the water level in the rear channel is above the surrounding 

 water level. 



In Figure 16, the elapsed time between successive photos is one- 

 eighth second. The flange facing the wave generator acts as a flat plate 

 along the wave front. A breaking bow wave grows toward the generator and 

 curls around the pile channel until the crest passes (Fig. 16, e). 



31 



