has been completed. This work was partly sponsored by the Office of Naval 

 Research, U.S.N., and was performed jointly by C. L, Bretschneider and . 

 R. 0. Reid, 



The dissipation functions for bottom friction and percolation given 

 by PUTNAM and JOHNSON ' and PUTNAM/ . , respectively, have been used in 

 the development of a general solution to the problem for (a) a bottom of 

 constant slope and (b) a bottom of constant depth. Special solution of 

 the general equations are also developed, from which it is possible to 

 calculate the actual wave height as a insult of a number of different com- 

 binations of bottom friction, percolation and refraction. A set of 

 nomographs have been prepared and can readily be used to determine the 

 energy loss of waves. 



The method developed is an improvement on the method prepared by 

 PUTNAM, in that it avoids computations by successive approximations. 

 Consequently, the work involved in determining the energy loss of waves 

 is greatly reduced. Furthermore, it is possible to calculate directly 

 the friction factor from wave records at two stations along the path 

 of wave travel. 



ii. Annual Technical Report . An annual technical report on wave 

 energy loss is practically completed and will be forthcoming before 

 1 May 19$3. Th3 technical report consists of two parts, one on the 

 theoretical work and one on the field work of the past twelve months. 



V. Massachusetts Institute of Technology, Progress Report for 

 Period 1 December 1952- 28 February 1953 . 



Tn the following is given the first progress report of the project as 

 of March 1, covering the period December 1 through February 28, vSiich from 

 now on will be followed by others at regular intervals. (As of June 1, 

 1953 the equipment assembly was nearing completion and tests were expected 

 to be under way during the summer). 



A. Experimental Equipment 



1. Wave Channel: The channel is part of the permanent equipment of 

 the Hydrodynamics Laboratory. It is 30" wide, 36" deep and has a working 

 section of 90 feet. A large steel entrance or exit tank and transition 



is provided at each end. The walls of the channel are of 1/2" plate glass 

 over the whole 90 feet. The bottom is horizontal and is of 1/2" plate 

 glass for UO feet and of l/k" steel plate for 10 feet and kO feet at 

 the upstream and downstream ends respectively. Construction of this flume 

 has been proceeding for the past year and is now rapidly nearing com- 

 pletion. 



2. Wave Generator: The generator proper consists of a horizontal 

 aluminum piston with a ^vertical face, suspended from a rail-moimted 

 carriage on top of the entrance tank. The carriage -piston is actuated by 

 a cam-operated, hydraulic servomechanisra and has continuously variable 

 amplitude and frequency. When completed this generator will be, to our 

 knowledge, the second wave generator in the United States, the amplitude 



-16- 



