Modeling the inhibition effect of straw checkerboard barriers on wind-blown sand

Straw checkerboard barriers (SCBs) are usually laid to prevent or delaydesertification caused by eolian sand erosion in arid and semiarid regions. Understanding the impact of SCBs and their laying length on eolian sand erosion is of great significance to reduce damage and laying costs. In this study, a three-dimensional wind-blown-sand model in the presence of SCBs was established by introducing the splash process and equivalent sand barriers into a large-eddy simulation airflow. From this model, the inhibition effect of SCBs on wind-blown sand was studied qualitatively, and the sensitivity of eolian sand erosion to the laying length was investigated. The results showed that the decrease in the wind speed in the SCB area oscillates along the flow direction. Moreover, the longer the laying lengths are, the lower the wind speed and the sand transport rate in the stable stage behind SCBs will be. We further found that the concentration of sand particles near the side of SCBs is higher than that in its central region, which is qualitatively consistent with previous research. Our results also indicated that whether the wind speed will decrease below the impact threshold or the fluid threshold is the key factor affecting whether sand particles can penetrate the SCBs and form stable wind-blown sand behind the SCBs under the same conditions. Although our model does not include the collision between sand particles and SCB walls, which makes the suppression of wind-blown sand by SCBs obtained from the current model conservative, our research still provides theoretical support for the minimum laying length of SCBs in anti-desertification projects.