Simulation Effect of Preventing Wind and Combating Sand of Simulated Sand-fixing Shrub in Wind Tunnel Testing

Simulated sand-fixing shrub is a new type of preventing wind and combating sand material which is made of high polymer materials mingled with antiaging agents in accordance with the simulation principle,its shape is as same as the shape of wild desert shrubs such as Artemisisa desertorum,Artemisia ordosica etc.having good effects in reducing wind and fixing sand.The different porosity of simulated sand-fixing shrubs were tested to their capacity of preventing wind and combating sand in the wind tunnel under the different tested wind speed,such as 7,9,12,15 m/s,respectively,discussed the correlation between amount of sand transport or wind speed and porosity in order to provide the theoretical basis for optimization design of shrub structure and practical application,the results showed as following: There were 3 wind velocity flow fields such as in front field of obstacle,in middle field of obstacle and in back field,respectively,in the whole flow processing under different wind speeds,but the major area of preventing wind field located in the H,0.5H in front field of obstacle and between 0.5H~3H in background of obstacle.The trend of decreasing average wind speed at different porosity simulated shrub was the same under different wind speed in the wind test tunnel,while the average range of wind reduction was between 35% to 46% was gradually decreased with wind velocity,but the range of wind reduction of the porosity β located among 36%~41% of simulated sand-fixing shrub which had 20 branches was the largest than those others.The amount of sand transport of simulated shrub increased with wind velocity,but effective function of combating sand in back field of different simulated shrub was significant difference,the porosity β between 36% to 41% of simulated shrub had a good at effective function of combating sand.According to the design of shrub structure of simulated sand-fixing shrub,production cost,protection benefit and practical application and so on,the simulated sand-fixing shrub of porosity β between 30% to 40% and number of branches between 16 to 20 was to found had a good shelter effect for preventing wind-blown and combating sand particles.