Windbreak effectiveness of shelterbelts with different characteristic parameters and arrangements by means of CFD simulation

Abstract

Shelterbelts can locally reduce wind speed in open terrains, moderating wind induced damage for agriculture and ameliorating growing conditions for crops. In this paper, Computation Fluid Dynamics (CFD) is adopted to clarify the effects of the characteristic parameters and arrangement of shelterbelts on their windbreak efficiency. The Darcy-Forchheimer canopy model is adopted to represent the vegetation, so modeling it as an isotropic porous medium. The shelterbelts are immersed in wind representative of the one expected in the atmospheric boundary layer and the numerical model is firstly validated against full-scale data. The parameters governing the shelterbelt aerodynamic performance, including shelterbelt width, shelterbelt length and opening length, are systematically varied, so providing a clear overview of the effects induced by their modification. The results show that the sheltering effect is enhanced as the shelterbelt width increases, while the effects of shelterbelt length are less pronounced in comparison. When there is opening inside the shelterbelt, the mean wind speed and turbulence kinetic energy behind the canopy is significantly increased due to the passage of airflow. General considerations regarding efficient shelterbelt arrangements are deduced by a comparison among L-, U- and rectangular-shaped types.