On the two-dimensional structure of short gravity waves in a wind wave tank

Abstract

Experiments on wind-waves in a laboratory tank are carried out for a variety of operational conditions. In addition to using a conventional wave gauge to determine the temporal variation of the surface elevation at the sensor location, independent measuring techniques such as 3D reconstruction of stereo video images and 2D laser slope gauge are applied in order to gain information on the three-dimensional structure of the wind-wave field. The consistency of results obtained by different methods under identical forcing conditions is examined to establish the limits of applicability and accuracy of each method. The accumulated results on the spatial and temporal coherence of the surface elevation variation, on the directional wave spectra, and on the probability distribution of the instantaneous surface slope directions demonstrate that the wind-wave field is essentially three-dimensional and short-crested.