Root Wind Tunnel Simulation Of Anti-erosion Resistance

Wind erosion is mainly a phenomenon in arid and semiarid areas where precipitation is rare, vegetation is sparse, wind is strong and frequent and the loose ground surface material is susceptible to be blown away by wind. It is a dynamic process which involves the mobilization, transport and deposition of surface by the erosive forces of the wind and is one of the main processes of desertification. Chinese scientists have paid a great amount of attention to wind erosion and carried out a great deal of research under the demands for combatting desertification since1980s. Some encouraging achievements of wind erosion such as influencing factors, control techniques of desertification have been made using wind tunnel tests and field investigations in typical areas. To sum up, the influencing factors of wind erosion mainly includes three aspects as following:In the first instance, factors of physical geography background such as climate, soil, vegetation, topography. Secondly human behavioral factors, such as the irrational economic activity of mankind and Grain for Green. Finally natural-Social Composite System, such as irrational human economic activity in arid and semi-arid areas aggravates region’s wind erosion under the background of global warming. There are two aspects of influencing factors that some can promote wind erosion and others can inhibit wind erosion, hence the significance of wind erosion influencing factors research is promoting positive aspect on inhabitation of wind erosion.A great deal of wind erosion research results shows that aerial parts of vegetation (such as canopy, crop residues) can promote aerodynamic roughness to reduce the energy transfer form airflow down to earth. Hence aerial parts of vegetation has positive effect for the inhibition of wind soil erosion. However, scientific report about wind erosion resistance ability of underground portion of vegetation (root) are very rare. Inspired by the previous studies, our wind tunnel test wants to reveal the anti-erosion effect of weed root by studying the wind erosion characteristics of different sample that contain different root content in different wind scale and different air flow.Following conclusions can be revealed by wind tunnel simulation:(1)Compared the turbulence characteristics between net flow and sand flow, we can find that the turbulence characteristics of sand flow is stronger than net flow. And turbulence characteristics get enhancing as the speed of airflow gets increasing.(2) Wind erosion modulus of sand flow is8-32times greater than net flow and the difference between sand flow and net flow increases as the speed of air get increasing. Sand flow is the main cause for wind soil erosion.(3) Wind erosion modulus of soil samples that mixed with of weed roots is less than those samples that did not mix with weed roots. Root of weed can improve the wind erosion resistance ability of soil.(4) The average effectiveness of wind erosion resistance ability of soil samples that mixed with of weed roots is28.24%, and effectiveness of wind erosion resistance ability of soil get to be enhanced as the content of weed roots in soil sample increase.(5)Although weed roots play a positive contribution to the anti-desertification and inhibit the occurrence and development of wind erosion, the turbulence of airflow can promote the development of wind erosion, especially the erosion of the sand flow cannot be ignored.