Numerical Simulation Of Sand Saltation On The Slope Of Dune

Desertification has become a major global environmental problem, and China is one of the most serious countries which were influenced by desertification. Desertification is the main manifestation of sand movement.There are three kinds of movement of sands namely, creep, saltation and suspension.In the three movement, saltation is the most important way, accounted for about 3/4 of the moving sand, and saltation is the main cause of formation of sand dune.In order to control and solve the problem of desertification, we should analysis on the mechanical characteristics of the sand saltation,because it is the basic work in researching saltation.In nature, it is a very common phenomenon that the movement of sands on the inclined bed surface.This paper will research saltation on the windward of sand dune, and the main contents are as follows:1、The acceleration effect of the wind field on the windward of sand dune makes the structure of the wind field more complex than that of the wind field on the flat bed.In this paper,we calculate the wind field on the windward slope of sand dune by Fluent software,and the different positions of the wind field is obtained on the windward slope of sand dune.Then,we get a fitting formula to describe the wind field near the sand dune,and it can be applied in engineer easily.2、In this paper,we calculate the mechanical progress of the sand saltation on the windward of sand dune by numerical simulation,and the gravity and drag force of sand in saltation are quantitatively analyzed.Then we discuss the mechanical progress of the sand with the variation of sand take-off position,initial take-off speed,sand dunes windward slope angle.I hope that it can lay a foundation for further research on sand saltation on the sand dune.3、The mass flux profile is calculated by computer numerical simulation.It is obvious that mass flux profile has stratification characteristics with saltation height increase.And sand take-off position,windward slope angle has a significant effect on mass flux profile,and an explanation is also proposed.The streamwise sand tranport rate is also calculated in this paper.