Experimental determination of wavelengths in the presence of a mean current.
413 - 431.
This paper describes a simple method for determining the wavelength of small amplitude waves under laboratory conditions where reflected wave components are present both with and without a mean current flow superimposed. It assumes a locally horizontal bed but requires no a priori assumption concerning the form of thr dispersion relation with a coexisting current. Synchronous measurements of the water surface recorded along any straight line are analysed to yield Fourier coefficients at each location. It is then shown that for all practical conditions excluding a perfect standing wave, the average rate of change of wave phase in the chosen direction can be related directly to the component of incident wave number in that direction, irrespective of reflection coefficient or relative current strength. The technique has bran applied to regular and bichromatic waves in a flume with an absorbing wave generator, and can also be applied in 3-D wave basins where waves and currents intersect at arbitrary angles. In combined wave-current experiments, by assuming the linear dispersion relation, it is also possible to estimate the effective current velocity. (C) 2000 Elsevier Science B.V. All rights reserved.
|Title:||Experimental determination of wavelengths in the presence of a mean current|
|Keywords:||waves, wavelength, reflection coefficient, wave phase slope, wave-current interaction, WAVES|
|UCL classification:||UCL > School of BEAMS
UCL > School of BEAMS > Faculty of Engineering Science
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