典型株型沙生灌丛对风沙流场影响的数值模拟 postprint

Abstract: The purpose of this study was to provide a theoretical basis for the rational selection of different vegetation types for wind and sand control in arid and semiarid areas. Fluent software was used to numerically simulate the flow field around three types of typical strains (altar-shaped, shuttle-shaped, and broom-shaped) of scrub to analyze the influence of different plant forms on wind and sand flow and verify the results using existing wind tunnel tests. Results showed that (1) The flow field around the three types of plants can be divided into five zones, and three eddies exist behind the plants. Due to the intensity of the eddies, during the initial phase of sand accumulation, shuttle- shaped and broom- shaped plants accumulated sand primarily at 6-7 H after the plant, whereas altar-shaped plants accumulated sand at 3 H. (2) Affected by the height layer of the maximum profile area of the plant, the minimum wind speed at 1 H after the three types of plant shrubs appeared at heights of 0.3, 0.4 m, and 0.8 m, and the optimal protection range of height was 0.2- 0.4 m, 0.3- 0.6 m, and 0.8- 1 m, respectively. The aerodynamic roughness of the three plant types decreased gradually, and the roughness of the altar-shaped plants was significantly higher than that of the other two plant types. (3) All three types of strains could effectively reduce wind speed in the range of -2-10 H. The wind protection benefits in the near-surface area after the strains are altar-shaped > shuttle-shaped > broom-shaped the wind protection benefits in the midaltitude area all decrease with increasing plant distance. (4) At T = 10 s, the total duration of sand accumulation around the three plants was 8.5 H, 6 H, and 4.5 H, respectively, and wind erosion existed to different degrees at 5- 5.5 m and 4.5-6 m from the entrance for Haloxylon ammodendron and Calligonum mongolicum, respectively. Compared with other plants, Nitraria tangutorum exerted a better sand-blocking effect. Hence, it is recommended to combine N. tangutorum with H. ammodendron and C. mongolicum in the construction of wind and sand fixation projects, so that the sand- blocking property of N. tangutorum can be effectuated, and the better windblocking effect of H. ammodendron and C. mongolicum can be utilized at medium and high altitudes.