Evolution law of wind-sand flow field of multi-row reed sand barriers and optimal spacing

The multi-row sand barriers have been widely concerned in the road sand prevention project because of its high effective wind and sand prevention impact. The spacing between sand barriers is the primary issue to be resolved in the arrangement of multi-row sand barriers. This study considered the reed sand barrier protection project of Xinjiang segment of Golmud–Korla railway as the research object, revealed the evolution characteristics of flow field and distribution laws of sand accumulation under the control of three-row sand barriers spacing by field monitoring, wind tunnel test and numerical simulation, and the optimal spacing of three-row reed sand barriers was explored by Design Exploration optimization analysis method. The results indicated the flow field presented a typically superimposed morphology of deceleration zones, acceleration zones, and recovery zones when airflow passed through the reed sand barrier. There was no deceleration zone ahead the second-row and third-row sand barriers before optimization. The flow field distribution was complete and each-row sand barrier can have a synergistic role in wind and sand prevention after optimization. The optimal spacing between three-row sand barriers decreased as wind velocity increased. The optimal spacing between three-row sand barriers corresponding to 10 m/s, 15 m/s and 20 m/s wind velocity was 25.5 m, 24 m and 20 m, respectively. The sand-blocking rates of corresponding reed sand barriers were 84.53%, 64.42% and 47.51%, which were 8.54%, 20.77% and 0.78% higher than before optimization, respectively. Therefore, it was suggested that the spacing of three-row reed sand barriers in the investigation area should be 20 ~ 25 m in order to make each-row sand barriers to play a role.