Accession Number : AD0071976

Title :   Laboratory Study of Short-Crested Wind Waves.

Descriptive Note : Technical rept.,

Corporate Author : CALIFORNIA UNIV BERKELEY WAVE RESEARCH LAB

Personal Author(s) : Ralls, G. C., Jr. ; Wiegel, R. L.

Report Date : JUN 1955

Pagination or Media Count : 33

Abstract : A laboratory program was undertaken (1) to determine the variation of wavelength, crest length, and wave velocity with fetch, water depth, and wind velocity; (2) to compare measured wave velocity with theory; and (3) to compare the results with those of 2-dimensional laboratory studies. Water depths from 0.5 to 2.5 in., wind speeds from 17 to 30 fps, and fetches from 0.5 to 10 ft were used. The still-water depth was checked, the fan was turned on, and the wind speed was adjusted for each run. The maximum wind velocity was recorded after steady-state wind conditions were reached, and motion pictures were then taken of about 12 successive waves crossing the field of view of the camera. There appeared to be no definite pattern to the waves. Three methods were used to obtain quantitative information on the short-crested pattern. A method analogous to the statistical method used to describe wavelength in the 2-dimensional model was most useful. Both crest length and wavelength had Gaussian distributions. The short-crested wave theory of Fuchs (NBS Circular No. 521, p. 187-200, Nov. 1952) predicted the measured wave velocities with a maximum deviation of 15%. An average deviation of 10% was obtained when the line intersection distribdtion method was used to determine the crest and wavelengths.

Descriptors :   (*WATER WAVES, STATISTICAL ANALYSIS), METEOROLOGICAL PHENOMENA, WIND, STATISTICAL DISTRIBUTIONS, WATER TUNNELS.

Distribution Statement : APPROVED FOR PUBLIC RELEASE