The spectral characteristics of wind-generated capillary waves

Abstract

An experimental study of wind-generated capillary waves has been carried out in a laboratory wind-wave tunnel. In this tunnel it was possible to generate a stationary homogeneous wave field and to vary the wind over a range of speeds. A technique which makes use of a Preston tube has been used to measure the shear stress at the air-water boundary. Measurements of surface elevation and wave slope spectra in the capillary range of frequencies were obtained. Equations describing the wave spectra equilibrium range under the action of wind shear, surface tension and viscosity are derived. For frequencies beyond 15 hertz the measured spectra are in satisfactory agreement with the derived equations. Comparisons with other existing data have also been made.