Some Research On Non-linear Characteristics In The Process Of Sand Movement

Sand-movement is the key content of the physics of blown sand, which occupies an extremely important position in the whole subject. So many researchers paid great attention to the sand-movement and have obtained many achievements. But the sand-movement is a very complicated system, which makes that there are some inevitable drawbacks in the study of sand-movement. For example, the application of the models for the threshold wind-speed of sand particles is seriously limited and mass flux models of sand particles have problems in their function range and structure.In this dissertation, we use the catastrophe theory to study the sand-movement. Firstly, based on the force acting on a single-particle, a discriminant formula of the threshold wind-speed of sand particles is established, and it is proved that the threshold wind-speed belongs to the cusp catastrophe. Then the basic equation of the cusp catastrophe is established based on coordinate transformation and catastrophe theory. Therefore a direct function is established between the basic variables, which are the characterization of the wind and sand, and the basic variables which are the characterization of sand-movement. Finally, through choosing and putting the different state variables and control variables into the basic equations of the cusp catastrophe, we can obtain the model of cusp catastrophe of the threshold wind-speed of sand particles and mass flux of sand transportation.The model is derived from the mathematics, which has a certain mathematical theory foundation. Compared with the former formation and the experiment date, it suggested the model in this paper get better results.