T.-M. No. 4 - March 1964 



Wave Height Prediction for Wave Generators in Shallow Water 

 by Cyri I J . Ga I vin, Jr. 



A simple method of computing wave heights generated by displace 

 ment-type, mechanical, wave generators in shallow water based on 

 approximate theory is presented. The heights of waves generated ai 

 approximately equal to 2itS/L times an appropriate linear dimension 

 of the generator measured normal to the stroke S, This relation is 

 shown to agree with hydrodynamic theory for piston and flap-type 

 generators and with actual measured data from four piston-type and 

 two plunger-type generators ot widely different character, for the 

 range of relative depth usually encountered in laboratory practice, 

 2Trd/L < I . 



T.M. No. 5 - April 1964 



Nearshore Tidal and Nontidal Currents, Virginia Beach, Virginia 

 by W. Harrison, M. L. Brehmer, and R. B. Stone 



Simultaneous measurements by Eul-erian and Lagrangian methods 

 were made continuously during a I -week period in the nearshore area 

 south of Cape Henry. Three Roberts Radio Current Meter stations 

 were established offshore, and 5 onshore stations were established 

 for longshore current and wave measurement. Collected data are 

 presented and a circulation model constructed which confirms earlier 

 speculation that nontidal drift describes a clockwise eddy movement 

 south ot Cape Henry, and southern limit of which is apparently near 

 Rudee Inlet. Diffusion was investigated in one of the tidal cur- 

 rents during ebb flow by tagging with rhodamine-B dye, and specific 

 information thereon is also presented. 



T.M. No. 6 - October 1964 



Development of a Method for Numerical Calculation of Wave Refraction 

 by W. Harrison and W. S. Wilson 



A procedure is described for calculation of wave refraction usinc 

 observed or hindcast deepwater wave characteristics, and high-speed 

 computer programs. An example of the method is presented in which 

 wave rays (orthogona I s) are brought from deep water in the Atlantic 

 Ocean to the shore at Virginia Beach, Virginia. The method is in the 

 developmental stage but promises rapid and accurate calculation for 

 routine determinations. T.M. 6 has been superseded by T.M. No. 17. 



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