Experimental Research On Sand Incipience Law In Wind-Blown-Sand Two Phase Flow

The law of sand incipience is the connection of microcosmic mechanism research on wind-blown-sand two phase flow and macrocosmic engineering application. Whether sand can saltate from sand bed surface and quality of sand incipience are very important to the sand transport and the form of wind-blown-sand. The quality of sand incipience involved with many kinds of parameters, such as incipient velocity, incipient angle etc. Our research depends on the advantage of cross-knowledge and makes a research on this subject by Gas-Solid Hydromechanics theory and PTV measure technology. Our research tries to understand sand incipience and wind-sand flow structure, find a new way to research the wind-blown-sand flow.Our research observes the wind-sand flow phenomena in outside field. Then establish a wind-blown-sand flow experimental set and reformulate the phenomena in lab. Our research analyzes desert phenomena and physiognomy characteristics with Gas-Solid Hydromechanics principles. The typical phenomena include sand incipience, sand ripple and sand erode. Our research takes PTV technology to obtain data in the experimental set. The movement data of sand are aimed near the sand bed surface. Out research demarcate the error of PTV method and provide a new way to research the dense wind-blown-sand flow.Our research obtains absolute fluent incipience and general incipience information of sand thickness field and velocity field. Firstly proposed a conclusion that the ratio of incipient efficiency on fluent and general incipience varies with wind speed. Our research analyzes comprehensively the sand data, such as thickness distribution, velocity distribution, frequency distribution of sand incipience velocity, expatiates the behaviors of these two sand incipiences in wind-blown-sand flow, then our research amends some deficiency of relative researches. In the extended experiment we modulate the sand grain diameter and air humidity to contrast with the natural result, discuss the effect of diameter and humidity on sand incipience, propose some ideas and methods to control sand transportation and formulation of wind-blow-sand flow.