Study On Numerical Simulation Of Wind-Blown Sand Morphology Under Complex Wind-Flow Field

Sand flow is formed by airflow to carry a variety of different size sands, and sand occur at different distances and form of displacement of a phenomenon. In the dust bowl during the formation of landforms, called Aeolian landforms. Formed this landscape is the ground surface loose sediments were airflow caused by wind erosion, transportation and deposition.In the desert, sand movement and sand geomorphology is the most popular movement of sand surface, their process of change flow field characteristics and composition of sand surface are closely related, so the sand ripple is the most fundamental and common aeolian geomorphology in desert. In normal circumstances, the rippled geometry is neat and regular,but due to the natural environment in the wild wind direction is not regular, rippled shape is not exactly the same, the interaction between the airflow and sand so that the shape of the sand ripples and aeolian geomorphology are very complex and diverse.Previously, many scholars through field observation and wind tunnel testing has done a lot of research, so sand has been further developments in the field of physics. In recent years,as computer technology advances, numerical simulation has become an important method of mechanism study of sand. Numerical simulation method of the field and wind tunnel test data and analysis results as a basis for simulation, set up the equations of motion of sand. The equation is solved by computer, will receive numerical simulation results were compared with experimental results, to research a lot of convenience.This paper to study the problem of desertification caused by wind-blown sand movement and is studied in detail in the basic theory of gas flow under the action of wind-blown sand movement, and the establishment of mathematical model of wind-sand flow field. First of all based on the theory of fluid mechanics, constitutive equations of the flow field are described in detail, and incompressible flow field Navier-Stokes equations are discretized into a two-dimensional differencing lays the theoretical foundation for subsequent numerical simulation. And then from a dynamic perspective, analysis of several main forms of grain,including the jumping, creeping, suspended and crash conditions, and based on furtheranalysis of the sediment flow field and its process of building constitutive equation. Finally,the c programming language to implement different Reynolds numbers of cavity flow models and models of complex flow field numerical calculation of flow state platform, and both the model and sediment flow model coupling implements different Reynolds numbers numerical simulation of the appearance of Aeolian processes. In order to verify the correctness of simulation results, but also to make an objective explanation of the mechanism of wind-blown sand movement and built a wind tunnel experiment platform of this study and the wild wind-tunnel experiment by experimental research, master a number of wind-blown sand movement rules.