Investigation Of Parameters In Two-phase Model For Windblown Sand Movement And Characteristic Of Mass Flux Distribution

Windblown sand movement is an important cause of soil erosion and sand storm. So study on the mechanism of windblown sand movement is essential in controling and governing of sand. Windblown sand movement is a typical air-solid two phase movement. Many researchers use the numerical simulation method to study the windblown sand movement. But they always ignore the interaction of parameters in the model. So this paper investigate the parameters in windblown sand movement with the help of Fluent. And then discuss the factor effected on the distribution of mass flux in height based on these parameters.Firstly, introduce the basic control equations in two-phase model. There are7parameters in the equations. The value is determined by their definition. Then, we confirm4of them and have the kinetic viscosity, momentum exchange coefficient, particle restitution coefficient been discussed further.Secondly, using the numerical simulation method of Euler two-phase model, the effects of the kinetic viscosity μs,kin, the momentum exchange coefficient β and the particle restitution coefficient ess on windblown sand movement are analyzed. The results demonstrate that the kinetic viscosity μs,kin affects the sand emission rate over sand bed, the momentum exchange coefficient β changes the development of streamwise sand transport rate, and the vertical distribution of sand mass flux varies with the particle restitution coefficient ess. The parameters obtained through numerical simulation are utilized to compute the windblown sand movement. And the characteristics of the windblown sand movement demonstrated by Euler two-phase model are in good accordance with those given in former experiments and numerical simulations. It shows that the parameters are suitable for the simulation of the windblown sand movement.At last, the distribution of mass flux in height is investigated with parameters above. The results show that the precision of the grid affects whether the layered structure of mass flux can be found. In the case of single sized sand, the distribution of mass flux is more layered with the increasing of frictional velocity when the size of sand is fixed. And in the same frictional velocity, the height of saturated layer reduces with the increasing size of sand. At a high wind speed, the moving large grains affect the small grains. It can be found that the distribution of mass flux of small grains appears layered structure. And the height of saturated layer is as multi times as the single sized sand.