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沙地云杉(Picea mongolica)为常绿针叶乔木,可作为荒漠区防护林体系建设的优良植物材料,其株高和植株构型明显区别于杨树等传统的防护林树种。因此,本文通过风洞模拟实验,在8、10、15m·s-1的风速条件下,研究了沙地云杉农田防护林单林带前后的风速流场特性和防风效能。单林带采用3种配置模式,即两行等株行距(Ⅰ型)、两行“品”字型(Ⅱ型)和四行簇状“品”字型(Ⅲ型),基于垂直风速流场对3种模式进行了比较。结果表明:(1)3种配置模式沙地云杉防护林带前后垂直高度上的风速流场分布特征有很大区别,相同配置模式的流场分布特征相似,随着风速的增大,风速流场的等值线变得更加密集。(2)3种配置模式防护林带前后垂直高度的风速加速率依次为Ⅰ型>Ⅱ型>Ⅲ型。(3)林带后20 H范围内1~20cm高度上防风效能依次为Ⅲ型(47.2%)>Ⅱ型(37.3%)>Ⅰ型(16.2%)。研究结果可为沙地云杉防护林配置理论研究奠定基础,为沙地云杉在农田防护林建设中的实际应用提供依据。
Picea mongolica is an evergreen coniferous tree, which can be used as an excellent plant material for the construction of shelterbelts in desert areas. Its plant height and plant configuration are obviously different from the traditional shelter tree species such as poplar. Therefore, this paper studied the wind speed and wind-field performance before and after single forest stand of Picea mongolica farmland shelterbelt under wind speed of 8, 10, 15 m · s-1 by wind tunnel simulation. The single forest belt adopts three kinds of configuration modes, namely, two rows and rows spacing (type Ⅰ), two rows of “type” (Ⅱ type) and four rows of clusters “type” (type Ⅲ) The vertical velocity flow field compares the three modes. The results show that: (1) The distribution pattern of wind velocity at the vertical height of Picea crassifolia shelterbelts is very different among the three allocation patterns. The distribution pattern of flow field in the same arrangement pattern is similar. With the increase of wind speed, The contour of the field becomes more dense. (2) The wind speed accelerating rates of vertical and horizontal shelterbelt with three kinds of allocation modes are Ⅰ> Ⅱ> Ⅲ. (3) The windbreak efficiency at the height of 1 ~ 20cm in the range of 20 H after forest belt was type Ⅲ (47.2%), type Ⅱ (37.3%) and type Ⅰ (16.2%). The results can lay the foundation for the theoretical study on the configuration of Picea crassifolia Shelterbelts and provide the basis for the practical application of Picea mongolica in the construction of farmland shelterbelt.