Research On Numerical Simulation And Feature Structure Of Grass Sand Barrier For Mechanized Sand-fixing

Desertification damage to the environment is serious all over northern and western China. Intechnical equipment means of desertification control, the checkerboard grass sand barrier is one of themost successful and widely used methods of sand fixation engineering. However, the current researchesof grass sand barrier mechanism still has defect in elaboration of its function. While successfullydeveloped a grass barrier automation laying equipment, the lack of the basic role of sand barrierproduced hamper effect on the application and popularization. In this paper, practical engineering research and application of the planting of grass sand barrierwas the research goal. The study was started from straw checkerboard barriers that widely used withsand-fixing function; then the sand barrier surface morphology aerodynamic shape research wasconducted by collecting sand barrier, sand beds, sand dunes and desert topography characteristics data;on the other hand, the mechanism of the flow field and blocking sand forming method affected by thebasic and grid structure of grass sand barrier was studied, by sand dynamics, fluid dynamics andcomputational geometry, such as research tools. For grass sand barrier mechanism and application of research methods, based on turbulence theory,this paper put forward that the phenomenon of sand flow field locally stable was caused of inducedvortex formation behind the sand barrier, and a numerical simulation algorithm was proposed to verifyand analyze the effect of wind prevention and sand fixation by the stable induced eddy current structurebehind sand barrier. This study established a relationship model between the stable positions, size andstructure of the vortex and sand barrier dimensional parameters, and through numerical simulation CFD,certain sizes form of induced eddy behind sand barrier, mechanism of action and the size and othercharacteristics rule were obtained. Research on the use of two-phase flow simulation was introduced and the role of vortex sandsurface intraction was interpated for its function as a windbreak, the shape of the curve function uses theangle of repose of the sand the edges as a design reference factors played a sand block to maximize flowcapacity capabilities. At the same time intervals can be based on different size adjustment, given thegrass sand barrier two design parameters:Size erosion intensity factor and volume erosion intensityfactor. Through rumerical simulation compared to traditional sand barrier structure and morphology,structure design has a positive role in the sand hexagonai shapc and the shape of sand pits in the surfaceof the vortex, quadrilateral sand-binding straw checkerboard barriers model results with the current useof construction, compared with more good production characteristics and coverage eddy size, process characteristics. Research based on the overall morphology of the terrain and sandy grass sand barrier,combined with sand barrier effect of the structured form of space, established its role model, gives theoptimized shape of the sand pit in the vortex of the grass and sand barrier model can design practices toimprove operations and equipment play a role. The conditions under non-planar flow field of sand dunes in the pressure drag and friction dragreduction measures fluid mechanics methods. Using the k-ε model for structured turbulent vortices formdimples under simulated conditions, the principle described inhibit separation of the boundary layer,the parameter calculation based on the experimental model of the structure size of the vortex. Througha combination of sand dune barrier model, selected and terrain contours adapt to changes in wind sandbarrier polygon shape, given the size of the sand barrier filling bunkers equilibrium parameters erosionintegral condition. For dune grass checkerboard barriers weaken the role of the nature, the main theory discovery is anon-smooth surface drag reduction, according to a newly designed sand barrier between the pit curvemodel, re-verify the condition of the structure of the vortex generator. Combined with the results ofnumerical simulation and geometric methods to achieve with less material, eddy big goals, and design asand barrier morphology hexagonal pits and using CFD software to simulate and study the results of theplanning results improved methods and parameters. By analyzing the role of the boundary layer nearthe surface of the flow field pits on the surface of the results of different structures. With a simpleone-size straw checkerboard barriers formed contours and topography pressure to adapt to multi-sizecheckerboard barriers polygonal pits, boundary layer flow field characteristics of a more stable, betterable to weaken the role of the sand dunes global. This study was inspired by when straw checkerboard barriers in the wind and sand successfulapplication process, first through field visits, found the grass in the sand box form a stable state, theinternal morphology showing pits. Through the above principles, this paper equipment of large-scalesand technical equipment requirements, proposed the relational model eddy and sand barrier, as well asa number of parameters to control the sand and the sand barrier and process methods. This inhibitingeffect by a simple method is not the force of inertia of the surface of the sand flow, but through the useof viscous properties of the fluid, the inertia of the kinetic energy is converted into shear directionvortex circulation kinetic energy created in favor of the existence of a stable vortex is generated andspatial dimensions conditions, and ultimately rely on this type of surface and stable pits polygonalstructure weakened the dominant wind shear inertia, reducing the migration of sand towards thedominant wind speed, so as to achieve the effect of wind and sand to stabilize the sand bed, furtherguidance can play a role in theoretical and applied research in the application process fixed dunes anddesertified land in.