Journal of Natural Disaster Science

IMPROVEMENT OF BLOWER TYPE SNOW FENCES BY CONTROL OF THE SHEAR LAYER

Hiroyuki HANIU
Associate Professor, Kitami Institute of Technology
Hiroshi SAKAMOTO
Professor, Kitami Institute of Technology
and
Kazunori TAKAI
Research Scientist, Kitami Institute of Technology

(Received 18 September, 1995 and in revised form 18 December, 1995)

Abstract

A blower type snow fence with a new configuration was developed for the prevention of snowdrifts and to improve visibility on roadways. The design was in accordance with hydrodynamic principles, and its performance was evaluated in model wind tunnel experiments in which natural snow was used to simulate blowing snow. Snowdrifts and visibility blockage behind the snow fence were found to be caused by the rolling-up of the gap flow that passes through the bottom part of the fence. This rolling-up of the bottom gap flow could be prevented by controlling the rolling-in of the shear layer separated from the top part of the fence. On the basis of this finding, a perforated plate was placed at the topmost part of the fence in order to weaken the rolling-in of the separated shear layer by diffusing the steep velocity gradient across the layer.

Key words

snow fence, visibility, traffic difficulties, blowing snow, shear layer control, perforated plate