Optimal design for vegetative windbreaks using 3D numerical simulations

Abstract Vegetative windbreaks are widely used to control wind erosion by reducing wind speed and attenuating sand movement, which motivates systematic research on optimal design for vegetative windbreaks. In this study, at the wind-tunnel scale, we conducted 3-D computational fluid dynamics (CFD) simulations with a realizable SST k-ω turbulence model that incorporates realistic geometries of vegetative windbreaks (Artemisia and Salix) to investigate wind dynamics around vegetative windbreaks and aid optimal design in aeolian engineering practice. The modified CFD models for vegetative windbreaks were first validated by comparing results with those from wind-tunnel experiments. Furthermore, we developed two new indexes (mRc and mBEI) based on the reduction coefficient ( R c ( x , z ) ) and barrier effective index (BEI) to evaluate the shelter effect. Optimal designs including the structural parameters and arrangements for vegetative windbreaks were then determined as follows: (1) three-row windbreaks were more effective for both Artemisia and Salix windbreaks; inter-row spacings of 2.5–3hA and 1-1.5hS were optimal (where hA and hS are the heights of the shrubs) for Artemisia and Salix windbreaks, respectively; (2) a staggered arrangement worked better for both monospecific windbreaks; (3) a two-row-one-belt system with inter-belt spacing of 8hA and 10hS was optimal under middle-velocity conditions, while a three-row-one-belt system with inter-belt spacing of 16hA and 16hS was optimal under high-velocity conditions; (4) multispecific-vegetative windbreaks were optimal when considering velocity reduction, while a Salix-only windbreak system was optimal for shelter distance. This research is expected to advance fundamental understanding of wind dynamics around vegetative windbreaks and provide references for building vegetative windbreaks in arid regions.