T.M. No. I 15 - June 1959 



Suspended Sediment Sampling in Laboratory Wave Action 

 by John C. Fa i rein i 1 d 



Data and some analysis on the quality of sediment placed in 

 suspension by wave action are presented. The data were obtained 

 in laboratory wave tanks and concern the collection and analysis of 

 wave-induced suspended sediment using waves of both small scale (2 

 to 6-inch heights) and relatively large scale (2 to 6-foot heights). 

 Quantitative analysis relates principally to the effect of water 

 temperature on concentration and size characteristics of suspended 

 material. However, considerable discussion is devoted to procedures 

 and techniques for sampling suspended material and the physical 

 procedures governing its behavior. 



T.M. No. I 16 - July 1959 



On the Theory of the Highest Waves by J . E. Chappelear 



Properties of the highest periodic gravity waves which can exist 

 in steady two-dimensional flow, neglecting viscosity, are calculated. 

 The "highest wave" is defined as one satisfying the criterion of 

 Stokes that the particle velocity at the wave crest be equal to the 

 wave velocity. The theory is valid for all values of the parameter 

 d/T^ greater than 0.2 ft/sec^. The highest wave in deep water, whose 

 properties were first calculated by Michel I and Havelock, is obtained 

 as a specia I case. 



T.M. No. I 17 - August 1959 



The Damping of Oscillatory Waves by Laminar Boundary Layers 

 by Peter S. Eag leson 



Results of an analytical and experimental investigation of the 

 shea-ring stresses exerted on a smooth bottom by passage of oscil- 

 latory water waves are presented. Force measurements, including 

 time-history of instantaneous force during passage of waves and 

 simultaneous measurements of instantaneous wave characteristics 

 were made and corrected for pressure and inertia forces to obtain 

 net tangential forces. Average resistance and damping coefficients 

 were derived in terms of wave properties. Analysis of results using 

 these coefficients showed bottom shearing stresses greatly exceeded 

 those predicted by theory. The boundary layer was then assumed to 

 be disrupted each half cycle due to flow separation, and periodic 

 regrowth of the layer was calculated by the approximate momentum 

 technique. Resistance and damping coefficients calculated on this 

 basis generally show excellent agreement with experiment. 



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