梭梭(Haloxylon anmodendron)林带防风效果的风洞试验

Wind tunnel test of wind speed reduction of Haloxylon anmodendron forests with different configuration

梭梭(Haloxylon anmodendron)是荒漠地区重要的固沙灌木,株高、构型与防风固沙乔木具有明显差异。通过风洞模拟实验,在12 m·s-1风速条件下,对3种高度和密度的梭梭林带模型的风速流场和防风效果进行了研究。结果表明:不同配置的梭梭林带模型后风速流场差异显著。1~2 cm高的梭梭林带后风速频数集中在8~8.7 m·s-1;4 cm高的梭梭林带后风速频数集中在7~8 m·s-1,平均防风效能分别为38.49%、32.29%、26.88%,有效防护距离分别为10H、7.5H、5H,优于1~2 cm高的配置类型。其中4 cm高、株行距2 cm×2 cm的林带后风速恢复迅速,最大风速大于等高度其他两种株行距的林带;高度1 cm、株行距2 cm×2 cm林带防风效果优于同高度密度稀疏的林带;2 cm高、株行距4 cm×4 cm的林带与1 cm高、株行距2 cm×2 cm的林带后的最小风速接近,表明随着梭梭林带高度的增加,林带密度优势开始减弱。因此合理的株行距有助于梭梭林带长期发挥最大防风效益。

Haloxylon anmodendron is an important sand-fixing shrub in the desert area.Its plant height and configuration are significantly different from those of trees.In order to explore the wind-proof effect of different configurations of H.ammodendron,this paper studied the wind speed flow field and wind-proof effect of different heights and densities of H.ammodendron model by wind tunnel simulation experiment under wind speed of 12 m·s-1.The results showed that there were significant differences in the velocity of the post-wind flow in the nine species of H.ammodendron.The wind speed of the H.ammodendron with a height of 1-2 cm was concentrated at 8-8.7 m·s-1 and the wind speed of the H.ammodendron with a height of 4 cm was concentrated at 7-8 m·s-1;The average wind protection performance of A3,B3 and C3 is 38.49%,32.29%and 26.88%,respectively.The effective protection distance is 10 H,7.5 H and 5 H respectively,which is better than other configuration types.However,the wind speed of the forest belt with a height of 4 cm and a row spacing of 2 cm×2 cm recovered rapidly,and the maximum wind speed was greater than that of the other two plant spacings.In the 1 cm height of H.ammodendron,the wind-proof effect of the density of 2 cm×2 cm(A1)H.ammodendron is better than that of the same height forest belt(B1,C1).The minimum wind speed of the forest belt with a height of 2 cm and a row spacing of 4 cm×4 cm(C2)is close to that of a forest belt with a height of 1 cm and a row spacing of 2 cm×2 cm(A1),indicating that the density advantage of the forest belt begins to decrease as the height of the H.ammodendron belt increases.Therefore,reasonable plant spacing can help the H.ammodendron belt to maximize its wind protection benefits.