Sand, wind and statistics: Some recent investigations

Abstract

A survey is given of work recently carried out in the Faculty of Science at Aarhus University. The paper is in two parts. The first part concerns the dynamics of grain movement and wind flow and discusses (i) a model for the process of sand saltation together with some related experiments, (ii) the influence of thermal instabilities and surface inhomogeneities on wind profiles, and some wind tunnel experiments on the pattern of wind flow over model dunes whose crest line form an oblique angle to the wind direction, (iii) wind tunnel studies of the progress of sand grains along a sand bed, grains being marked by dyes or by a cover of radioactive gold. Part two reports on a variety of investigations that involve some use of the hyperbolic distributions but are otherwise quite distinct. The subjects are (i) the shape of sand grains, (ii) classification of sand sediments, (iii) sieve calibration, (iv) accelerations in turbulent wind fields.