| The distribution of airborne debris around high-speed snowplows affects visibility and thus road safety. A combination of calculations, windtunnel experiments, and road trials are presented to provide knowledge of debris distributions and to obtain understanding of the mechanisms that can reduce suspended debris. Measurements obtained around windtunnel models show the influence of a variety of plow geometries on the location of debris around plowing trucks. Debris trajectories were calculated around plows with and without overplow deflectors by solution of Reynolds-averaged Navier-Stokes equations with cutting-edge and particle-tracking models. Calculations extrapolated windtunnel results over the wide range of snow conditions from light powder to slushy ice. Road trials compared visibility of conventional and modified snowplows with image analysis that quantified visible area, contrast and color intensity. In full scale tests, snow did not blow overtop of plow configurations that had trap angles less than 50 degrees, as predicted in windtunnel and computational results. Packing and junction flaps deflected discharge snow back into the consolidated discharge stream and decreased the amount of loose debris. Side-mounted hopper vanes kept rearward-facing surfaces clearer and made rear lighting and signage more effective. The visible area of high-speed snowplows outfitted with overplow deflector, packing flap, junction flap and hopper vanes was measured to be more than 50% larger than conventional plows for following motorists in all wind conditions and this was linked to reductions in the quantity of debris in the downstream snow cloud. |
