Kinematics of turbulence converted by a random wave field.

Abstract

Discusses analysis of field measurements of velocity at various depths beneath wind generated waves of Lake Ontario. Linear statistical techniques are used to separate the data into wave and turbulent components. The turbulent velocity spectra show a large enhancement about the central wave frequency. A five-thirds frequency dependance can be seen both above and below the central peak, although the dissipation density is larger at high frequencies. Suggests that the spectral shape can be explained by a generalization of Taylor's hypothesis for the case when frozen, isotropic homogeneous turbulence is convected bodily by the orbital velocity field associated with the surface wave motion. Discusses how drift currents or a random wave field broaden the line spectrum into a continuum. Calculates the asymptotic frequency dependence for a particlar case. (C.J.U.)