T.M. No. I 18 - August 1959 



Wave Variabil ity and Wave Spectra for Wind-Generated Gravity Waves 

 by Charles L. Bretschnelder 



Wave records from a wide variety of locations have been utilized 

 in a statistical analysis of the probability distributions of wave 

 heights and wave periods; and a family of wave spectra which allows 

 for an arbitrary linear correlation between wave height and wave 

 period swuared is suggested. It is proposed that in early stages of 

 wave generation, the correlation is nearly unity, but as the gene- 

 ration proceeds, the correlation decreases, ultimately approaching 

 zero for a fully developed sea. 



T.M. No. I 19 - August I960 



Sand Movement by Wind Action (On the Characteristics of Sand Traps ) 

 by K. Horikawa, and H. W. Shen 



Results by other investigators for wind pattern and velocity 

 profile and their relation to sand movement are review and dis- 

 cussed. Movement of sand by wind is studied in a laboratory wind 

 tunnel to verify these relationships, separating that moved by 

 processes of surface creep and saltation. Several types of sand 

 traps are calibrated and their efficiency studied, and character- 

 istics discussed. 



T.M. No. 120 - August I960 



The Prediction of Hurricane Storm-Tides in New York Bay 

 by Basi I W. Wi I son 



This report is concerned with the solution of the problem of 

 correlating on a two-dimensional basis the meteorological parameters 

 of severe offshore storms with the known surge induced by them in 

 New York Bay, and with the appl ication of the results to the pre- 

 diction of likely effects in New York Bay from a design-hurricane 

 of given strength traversing a given path at a given speed. Using 

 an empirical method with some degree of theoretical guidance, a 

 correlation-prediction formula is evolved, and its application to 

 design hurricane (1938) showed maximum storm-tide height of 8.9 feet 

 in reasonable agreement with an empirical estimate based on central 

 pressure in the hurricane. Parallel surge predictions are made for 

 design hurricane (1944) for three cases of storm size and speed, and 

 that predicted for a probable maximum hurricane turns out to be 

 13.3 feet. The flux and discharge of flood waters through the bay 

 entrance channel are also investigated. 



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