The Flow Field And Sand Movement Characteristics On The Leeward Side Of The Windbreak And Sand Retaining Wall

The current problem of sandstorm disasters in China is still extremely serious.The desertified land has more than 2.6 million square kilometers,accounting for about27% of my country's territory,and this number is still increasing.As one of the most commonly used sand control methods,the wind and sand retaining wall is very important to study the flow field around the wall and the characteristics of sand movement.In this paper,based on ANSYS Fluent software,using the Euler two-fluid model,a wind and sand retaining wall is added to the flat sand bed,and according to different incoming wind speeds and different sand particle sizes,the sand transport law in the flow field around the sand retaining wall is discussed.,to provide an effective theoretical basis for future sand control work.The main research contents of this paper are as follows:(1)Take the Euler two-phase flow as the calculation model to simulate the previous wind tunnel experiments,and compare the simulation results with the previous experimental results,which proves that Feasibility of the Eulerian two-phase flow model.(2)Set up non-sand retaining walls,non-porous sand retaining walls and 0.4porosity sand retaining walls in the flow field,analyze and compare the characteristics of the flow field on the leeward side of the sand retaining walls and the movement characteristics of sand particles(ie: sand velocity,sand bed accumulation rate and single-width sand transport rate),the wind and sand resistance mechanism of the sand retaining wall is obtained.(3)For the non-porous sand retaining wall and the 0.4 porosity sand retaining wall,under different incoming wind speeds,the flow field on the leeward side of the sand retaining wall and the movement characteristics of sand particles were analyzed and compared.The greater the velocity of sand particles on the leeward side of the wall,the more serious the damage to the sand bed and the greater the sand transport rate per width.Therefore,it can be concluded that the sand retaining wall with a porosity of 0.4 has a better protective effect.(4)For the 0.4 porosity sand retaining wall,different sand particle sizes were selected for simulation,and the flow field and the movement characteristics of sand particles on the leeward side of the sand retaining wall were analyzed and compared.The sand particles near the surface of the sand bed will produce a larger single-width sediment transport rate,and the sand particles with smaller suspension scale and small particle size have smaller inertia and better followability,and the suspension scale is larger.(5)For the double-layer sand retaining wall model,the effective shelter distance of the sand retaining wall models with different spacings is analyzed and discussed,and the optimal spacing is 40 m.And analyzed the flow field and sand movement characteristics on the leeward side of the sand retaining wall under the optimal spacing,and found that the sand retaining wall model in this paper can only be used in the area where the maximum wind speed is lower than 30m/s.