A Slip-velocity Hypothesis Applied to Hydraulically Smooth Wind Flow Over a Snow cover

Abstract

An hypothesis relating the slip velocity for laminar flow over a porous surface to the specific permeability of the surface proposed by Beavers and Joseph (1967) is applied to the problem of estimating the surface shear stress on an extensive snow surface at low wind speeds. Vertical profiles of wind speed and the air permeability of the surface snow layer were recorded for five periods of neutrally stable, hydraulically smooth flow. The variation of the ratio of the slip velocity to the surface shear stress with the specific permability was examined. The data are compatible with the hypothesis, although they are too sparse to allow valid estimates of the coefficients in the hypothesis.