Velocity field measurements of flow around a triangular prism behind a porous fence

Abstract

The shelter effect of a porous wind fence on a triangular prism was experimentally simulated in a circulating water channel. A porous wind fence of porosity epsilon = 38.5% was installed in front of the prism model. The fence and prism model were embedded in a turbulent boundary layer at Reynolds number of about 3460. The instantaneous velocity field around the fence and prism model was measured using a two-frame Particle Tracking Velocimetry (PTV) technique. In addition to the well-known mean velocity reduction, the fence decreases the turbulent intensity and turbulent kinetic energy around the prism. Especially, at the top of the prism model, the turbulent kinetic energy is about half of that without the fence. Hy installing the fence in front of the prism, the length of the re-circulation region also decreases compared with that of the no fence case. (C) 1998 Elsevier Science Ltd. All rights reserved.