PART II: DESCRIPTION OF FACILITY AND EXPERIMENTS 

 Large Wave Tank 



10. The LWT was originally located at the Dalecarlia Reservation in 

 Washington, District of Columbia. Use of the tank at Dalecarlia, with a small 

 generator installed, began in 1955. The tank began full operation in 1956 and 

 was abandoned in 1973 when CERC moved to Fort Belvoir, Virginia. A new tank 

 of identical specifications, in which the wave generator from the tank at 

 Dalecarlia was used, was constructed at Fort Belvoir. The facility at Fort 

 Belvoir became operational in 1975 and was mothballed in 1983. Information on 

 the LWT at Dalecarlia is contained in a 1964 BEB report (Raynor and Simmons 

 1964), and a portion of the material in this section is excerpted from that 

 report. Only information relevant to the movable-bed experiments is given 

 here, so that only the Dalecarlia tank is of interest. 



11. The concrete tank was 635 ft* long, 15 ft wide, and 20 ft deep and 

 was located outdoors. A manually operated instrument carriage moved on hori- 

 zontal rails along the top of both side walls of the tank. The instrument 

 carriage carried personnel and instruments required to perform measurements. 

 Approximately one million gallons of water were required to fill the tank to 

 the standard operational depth of 15 ft. The tank was filled through either 

 of two 5-in. lines leading from an 8-in. freshwater main. Water was supplied 

 from the Dalecarlia reservoir. Filling normally required about 8 to 10 hr, 

 and valves could be set to automatically cut off at any predetermined level to 

 allow filling to take place during the night without loss of normal work 

 time. Pictures of the tank are given in Figures 1 and 2. 



12. The wave generator (Figures 3 and 4) consisted of a vertical bulk- 

 head 15 ft wide and 23 ft high mounted on a carriage. The carriage moved 

 back and forth along rails on the top of each wall of the tank; and two 42-ft 

 9-in.-long arms, connected to two driving disks at an adjustable eccentric, 

 transmitted the oscillatory motion to the carriage and bulkhead. Each disk 

 was 19 ft in diameter and weighed 14 tons. The disks were driven through a 

 train of gears by an 510-hp constant speed electric motor. Motion of the 



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

 (metric) units is presented on page 6. 



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