关键词: 沙地云杉(Picea mongolica), 农田防护林, 风洞模拟实验, 流场, 防风效能

Abstract: Picea mongolica is an evergreen coniferous tree which can be used for construction of shelterbelt system in arid area. However, its height and plant configuration are not same as traditional windbreak trees, such as Populus. In this paper, we analyzed the windbreak effect of Picea mongolica shelterbelt with different configuration using vertical wind velocity flow field in the conditions of 8 m·s^-1, 10 m·s^-1 and 15 m·s^-1 in the wind tunnel. Comparison was made among the 3 configuration modes:two rows with same spacing (type Ⅰ), two rows with triangle patterns (type Ⅱ) and cluster type with triangle patterns (type Ⅲ). The conclusions are:(1) The vertical wind velocity flow fields under different configuration before and behind the shelterbelt are different, whereas the vertical wind velocity flow fields under the same configuration are similar. The contoured velocity of flow field becomes intensive with increasing wind velocity. (2) The acceleration rate of wind velocity is type Ⅰ > type Ⅱ > type Ⅲ. (3) The windbreak effect at the height of 1-20 cm in 20H behind the shelterbelt is type Ⅲ(47.2%) > type Ⅱ(37.3%) > type Ⅰ(16.2%). The result will lay foundation for the theoretical study of Picea mongolica shelterbelt configuration, and offer reference for the construction of Picea mongolica shelterbelt system.

Key words: Picea mongolica, farmland shelterbelt, wind tunnel test, vertical wind velocity flow field, windbreak effects