Drifting-Snow Similitude—Transport-Rate and Roughness Modeling

This paper reports on results from a series of experiments in a boundary-layer wind tunnel concerning snow-drift control adjacent to grade separations on interstate highways. A new application of similitude principles making use of theoretical relationships involving drifting particulate material is presented. The primary modeling parameters are considered to be a mass-rate parameter and an aerodynamic roughness parameter. They are derived by considerations of mass-transport rate of material in saltation and the equivalent roughness height of material in saltation. The parameters are combined empirically to correlate model snow-drift data successfully as well as to predict equivalent full-scale wind speeds and storm durations. The combined parameter has been used to compare and evaluate a variety of drift-control techniques adjacent to an interstate highway grade-separation crossing.