【作者】 程旭；

【导师】 祁海鹰；

【作者基本信息】 清华大学 ， 热能工程， 2003， 硕士

【摘要】 沙粒起动规律是联系风沙运动微观机理研究和宏观工程应用的桥梁。沙粒能否起动以及起动质量如何，如起动初速度、起动角度等参数都直接关系到沙粒的输运和风沙两相流形成。本论文发挥交叉学科的优势，采用气固两相流体力学理论和PTV测量技术研究这一现象，从新的角度认识沙粒起动和风沙流结构，为风沙流动的研究打开了新的思路。本文建立了风沙流实验装置，对自然界中的风沙流动现象进行野外观测和实验室模拟。使用流体力学的基本原理解释沙漠中的沙粒起动、沙纹形成和沙蚀等常见现象和地貌特征。本文使用PTV测量系统在实验装置中获得了近沙面的沙粒运动信息，解决了一系列测量方法和图像处理中的实际问题，标定了实验中PTV技术测量数据的误差。本文分析了纯流体起动和综合起动条件下沙粒的浓度场和速度场信息，发现了两种起动的效能比随风速的变化关系。本文全面分析了沙粒浓度分布、速度分布和沙面上起动沙粒速度参数的频率分布等，阐述了两种沙粒起动方式在风沙流中的不同表现，并对相关研究资料中的不足进行修正。本文还拓展了实验条件，通过调整沙粒粒径配比和空气湿度，完成了对比性实验，并进一步探讨了粒径和湿度对沙粒起动的影响，提出了在沙漠工程中控制风沙流形成和沙粒输运的思路和方法。更多还原

【Abstract】 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.更多还原