2. Water Level 



Throughout the test program, the water level gage remained at the 

 same location, and prior to each run, the water in the tank was measured 

 and established at the desired level. 



3. Wave Height Measurement 



A resistance type stainless steel dual -wire probe was suspended in 

 the water in the estimated center of the flume at approximately the location 

 proposed for the device for the ensuing test run. This probe was fastened 

 to a flat carriage that spanned the width of the tank, and could roll from 

 one end of the tank to the other over level rails on top of the concrete 

 sidewalls. The wave-height sensing probe, once in position, was linked to 

 a 2-channel pen-motor recorder. The wave gage recorder system was balanced 

 and calibrated before and after each run of short or moderate duration, and 

 periodically during long runs. Also, the sensing probe was adjusted to 

 record I i near I y. 



4. Wave Height and Wave Period Calibration 



The eccentric arms of the wave generator control the length of the 

 blade movement which determines the height of the wave. The period of the 

 generator is, of course, the period of the wave and can be checked by stop- 

 watch. Approximately 3 minutes of wave action were allowed prior to 

 recording the waves for height analysis to allow tank effects to reach an 

 equilibrium state with respect to the waves being generated at that time. 

 After the 3 minutes, wave heights were analyzed immediately, and the eccen- 

 tric setting of the generator arms was altered until the desired wave height 

 was obtained. Then all wave action was stopped and the surface of the coal 

 in the flume was surveyed and its profile drawn. 



5. Profile Surveying Technique 



Two technicians surveyed the flume bottom profile. A technician 

 on the carriage sounded the depth of the coal surface with a modified 

 Philadelphia rod attached to the carriage and fitted with a foot to prevent 

 its penetration into the coal. A measuring tape, 40 feet long, was attached 

 to the inside wall of the flume where it could be easily read by another 

 technician who also pushed the carriage to the desired location and noted 

 the depth reading and its location on a data sheet. 



6. S lope Remol d i ng 



After a series of runs involving the use of the device, the bottom 

 was sometimes deepl'y entrenched and uneven. If this was the case, it was 

 felt that variable shoaling and reflection effects might well cause erroneous 

 results, and the coal bed was remolded. The wave conditions for. the run sub- 

 sequent to remolding were set on the generator and the water was drained below 

 the level of that segment of the bed to be remolded. Crushed coal was added 



