格状沙障内风速波动特征初步研究

通过对不同孔隙度格状沙障内风沙流中风速波动特征研究发现:风沙流中各高度层风速波动具有很好的相关性,其波动幅度随孔隙度的增加而减小;瞬时风速在时间序列上波动的均一性随不同高度间距离增加呈递减趋势;瞬时风速的波动性一方面受下垫面性质及外在环境条件的影响,另一方面与其所在高度层沙粒数量和运动状态有关.

Preliminary Research on Fluctuation Characteristics of Wind Speed over Checkerboard Sand Barriers

In this paper, an experimental study on fluctuation characteristics of wind speed within blowing sand flow over the Nylon checkerboard sand barriers with different porosities in wind tunnel in carried out. The experimental wind tunnel is 21 m in length and 1.2 m in width and height. The sampling heights are 1.0, 1.5, 3.0, 6.0, 12.0, 20.0, 35.0 and 50.0 cm respectively, and the temporal alternation of data collection is 2 seconds. However, the temporal alternation of data collection is a little long due to the instrument limitation, and the distribution of different sand barriers is simplex. Especially, the effects of porosity, pore shape, density and height of sand barriers on fluctuation of wind speed and transported sand amount need to be further researched using exacter instrument. The study results reveal that the fluctuation of wind speed over sand barriers is highly correlated with the height of blowing sand flow because the features of underlaying surface play an important role in affecting the energy of blowing sand flow; the fluctuation of wind speed is decreased with the increase of porosity of sand barriers; simultaneity of fluctuation of the instantaneous wind speed at deferent heights is decreased with the increase of the space between different heights; fluctuation of the instantaneous wind speed is affected by both underlying surface and environmental conditions, and is also related to wind-carried sand amount and movement status.