PART III: EXPERIMENT ARRANGEMENT 



Facility and Equipment 



91. Tests were conducted in a 150-ft*-long, 1.5-ft-wide, and 3-ft-high 

 glass-walled tank (Figure 20). The tank contained a 1/30 smooth concrete- 

 capped slope that began 69 ft from the generator board. The section between 

 the slope and the generator was horizontal. Waves were generated by an 

 electronically controlled hydraulic system that drove a piston- type wave 

 board. Displacement of the wave board was controlled by a command signal 

 transmitted to the board by a synthesized function generator for monochromatic 

 waves and by a microcomputer for irregular waves . The microcomputer can also 

 produce monochromatic wave signals for an operator- specif ied length of time. 

 Although the synthesized function generator can only send monochromatic wave 

 signals, it is independent of the microcomputer and operates until it is 

 manually turned off. The synthesized function generator was more convenient 

 to use if data collection was not necessary, such as when visual observations 

 were made . 



WAVE GAGES 



DISTORTED SCALE. 1H = 5V 

 TANK WIDTH = 0.+6 m 



Figure 20. Sketch of tank used in study 



92. The water surface elevation was measured with eight double-wire 

 resistance -type gages connected to the microcomputer by cables. The gages 

 were calibrated each day prior to testing. Gage 1 was located 30 ft from the 

 wave generator. Gages 2 and 3 were placed "seaward" of the bar and positioned 

 to measure wave reflection using the method described by Goda and Suzuki 

 (1977) . Gage 4 was placed near the point of incipient wave breaking. Gages 5 

 through 8 were distributed through the surf zone and used to measure wave 



* A table of factors for converting non-SI units of measurement to SI 

 (metric) units is presented on page 8. 



59 



