Section 6. TECHNICAL MEMORANDA OF THE COASTAL ENGINEERING RESEARCH CENTER 



T.M. No. I - January 1964 



Sand Movement by Wind by Pierre-Yves Bel ly 



Sand movement (deflation) by wind is investigated in a laboratory 

 wind tunnel, and results compared with formulas previously developed 

 by other investigators. Findings of previous investigators with 

 respect to rate of sand transport are reaff irmecj, but average flying 

 distance of sand particles was found to be much greater, possibly due 

 to method of calculation. Kadib (in Addendum I I ) .extends the in- 

 vestigation to a smaller size range and indicates threshold velocity 

 is best determined by experiment rather than formula when grain size 

 is < 0.20 mm. Moisture increases the value of the threshold shear 

 velocity of sand movement. 



T.M. No. 2 - February 1964 



Transportation of Bed Material Due to Wave Action by George Kalkanis 



A method is developed for use in determining rate of sediment 

 transport in a layer adjacent to the ocean floor. Method is applicable 

 only for conditions of unstable flow in this layer associated with 

 long surface waves of small amplitude where it is assumed sediment 

 particles in a bed are brought to a state of incipient equilibrium. 

 By experimental determination of the distribution of lift forces and 

 statistical analysis of turbulent fluctuations, an equation for the 

 rate at which sediment in the bed layer is oscillated and an ex- 

 pression for concentration of sediment in the oscillatory state are 

 developed. The concentration in combination with velocity distribu- 

 tion in bed layer associated with any incidental secondary flow can 

 be used to calculate transport rate of bed material in direction of 

 that flow. 



T.M. No. 5 - March 1964 



A Thermistor Probe for Measuring Particle Orbital Speed in Water 

 Waves by P. S. Eagleson and W.P.M. van de Watering 



A thermistor probe and the necessary additional electronic cir- 

 cuitry to measure temporal and spatial distribution of the magnitude 

 of the orbital velocity vector in water waves have been developed. 

 Considerations are presented which govern the choice of the thermis- 

 tor and circuitry according to the proposed use of the probe. A 

 steady-state calibration by towing the probe through a still body 

 of water is shown to be adequate for indicating, velocities in steady 

 motion of a water wave for a frequency up to 0.5 cps. Orbital 

 velocities of laboratory waves measured with the Instrument are 

 compared with those predicted by Stokes' theory. 



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