Preliminary computations involving the combination of wave generation and 
wave energy loss due to bottom friction have begun. 
Wilo Massachusetts Institute of Technology, Contract No. DA-l9-055-eng-16 
Progress Report dated September 17, 1953. 
1. Wave Channel. The channel is completed having been caulked and water 
tested ao as to be without leaks under the full head of three feet. 
2, Wave Generator. The hydraulic components, carriage, rails and 
feedback mechanism are completed and installed. ‘the piston is under con- 
struction at the present time. 
The manufacturer of the permanent, adjustable speed, cam drive has in- 
dicated a further delay in delivery, the data now being 15 October 1953. Con- 
struction of the adjustable stroke mechanism to be incorporated with the 
above drive will be completed by 1 October 1953. However, a temporary non- 
adjustable cam drive has been installed which produces the maximum generator 
stroke of 2 feet at a period of 1.90 seconds. The generator has been op- 
erated under these conditions with a still-water depth of 20 inches in the 
flume and has been found to be mechanically satisfactory. 
3. Baffles. Pilot tests were conducted in one of the laboratory's 
smaller wave channels to determine the most effective material to be used in 
dissipation of the wave energy behind the wavemaking piston. Tests on rock 
filled cribs, logs and automobile radiator cores in various positions and 
combinations indicated the latter to be the most effective. It was found 
that an optimum spacing of two such vertical baffles existed at which point 
the percent energy transmitted and reflected were both a minimum. 
The baffles and a beach of 15 to 1 slope have been installed in the 
wave channel. 
lh. The false bottom, fixed beach at a slope of 15 to 1 is being coat- 
ed with Ottawa sand of the size range passing the No. 20 sieve and retained 
on No. 25. This sand, the representative diameter of which is about 0.03 
inches, will be glued to the beach to provide roughness. The type and 
size range of the sand was chosen because it corresponds with that used in 
previous bed load studies in this laboratory. The steady-state hydraulic 
roughness of this sand has already been determined, and it is expected that 
valuable comparisons can be drawn between the steady and unsteady character- 
istics of bed load movement. 
5. A still-water depth of approximately 18 inches will be used in 
the wave channel and short waves of low amplitude will be generated. These 
waves will be referred to the equivalent deep water wave and their effect 
on the distribution of statistical samples of spherical particles will be 
studied. 
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