Simulating Airflow Around Flexible Vegetative Windbreaks

Abstract

AbstractVegetative windbreaks play an important role in reducing soil erosion and sand storms, which are widely applied in arid/semiarid regions. An optimal design of vegetative windbreaks is essential in aeolian engineering practice. In this study, three‐dimensional airflows around multiple arrangements of vegetative windbreaks were simulated using a modified Reynolds‐Average Navier‐Stokes (RANS)‐based computational fluid dynamics (CFD) model, based on which, optimal designs of vegetative windbreaks were discussed. We proposed a correction factor in the source terms of the momentum and turbulent transport equations representing the effects due to the vibration of the vegetative windbreaks, which was further calibrated using both simulated and wind tunnel experimental results. Moreover, a quantitative expression of the correction factors associated with structural parameters of vegetative windbreaks was established and verified. For optimal designs to reduce wind erosion, a suite of numerical experiments was conducted to find the optimal height, leaf area density, and vegetation fraction of the vegetative windbreaks under different free‐stream wind speeds. The results identified that under low free‐stream wind speed (6.4 m/s), the optimal parameters are 9.0 cm, 0.45 cm2/cm3, and 3.92%. Under moderate free‐stream wind speed (8.0 m/s), those optimal parameters are 12.4 cm, 0.47 cm2/cm3, and 3.92%. Under relatively high free‐stream wind speed (10.8 m/s), the optimal parameters are 12.4 cm, 0.47 cm2/cm3, and 8.00%. The results of the current study will aid in optimizing vegetative windbreak designs and preventing wind erosion in aeolian engineering.