Surface pressure characteristics on a triangular prism located behind a porous fence

Abstract

The shelter effect of porous wind fences on wind-blown dust was studied by measuring the pressure characteristics around a two-dimensional prism of triangular cross-section. The wind fence of porosity epsilon = 40% which was known to be most effective to abate the wind erosion was used in this study. The wind fence and the prism model were embedded in a thermally neutral atmospheric surface boundary layer over the suburb. The fence had the same height as the prism crest of 40 mm and Reynolds number based on the model height was Re = 2.6 x 10(4). We also investigated the effect of a back fence located behind the prism model and multiple back prisms on the pressure and wall shear stress on the prism surface. By installing the porous wind fence, the mean pressure and pressure fluctuations on the prism surface were decreased, and the wall shear stress on the windward surface of the prism was decreased up to : of that without the fence. When a back fence was installed behind the prism in addition to the front fence, the pressure fluctuations on the model surface decreased more than half. When several consecutive prisms of the same shape were located behind the fence, the shelter-effect of the porous wind fence was extended up to the 5th-6th prism. (C) 1999 Elsevier Science Ltd. All rights reserved.