几种常用风沙颗粒测速方法对比

摘要/Abstract

摘要： 沙粒运动速度是风沙颗粒运动学和风沙流（一种特殊的气固两相流）研究中的一个重要参数，受到风沙物理学研究者们的长期关注。风沙颗粒运动速度研究遇到的关键问题是测量方面的困难，目前已经尝试应用了多种测量技术。对几种常用测试手段——光电管测速计、高速摄影、粒子动态分析仪（PDA）和粒子图像测速仪（PIV）的测量结果进行了对比分析。光电管测速计、高速摄影法、以及粒子动态分析仪在研究颗粒速度的分布方面比较有用，而粒子图像测速仪则是一种全场测速技术，是测量特定区域内平均速度场时空变化的有用工具。上述几种测试方法所得的结果既有相似之处，但也存在较大差别。根据这些测速手段所得到的沙粒速度的概率分布特征是相似的，但测量结果所反映的沙粒平均速度与风速、粒径以及其他可能影响因子间的关系存在明显差异。目前的测量技术均不能直接测量贴近层或沙床表面的沙粒速度，而这些数据在研究地表颗粒的起动机制时是相当重要的。虽然用不同的测量技术所得出的沙粒平均速度随高度的变化关系均为幂函数，但这些幂函数的估算结果差别很大。基于对比分析，我们认为，各种测速技术均有其独特的测量原理，各有其优劣，但对其测量结果的可靠性尚无定论。所以，为了充分运用不同的测速技术，需要做大量的工作对其进行验证标定，研发一种可靠的技术来测量风沙流中的沙粒速度仍然是目前风沙物理研究的重要任务。

关键词: 风沙流, 颗粒速度, 测速技术

Abstract: The velocity of saltating particles is an important parameter in aeolian physics and represents a special case of a two-phase (gas particle) flow. Several techniques have been applied to measure the velocity of the blowing particles. In this paper, we review several commonly used measurement methods: photoelectric cells, high-speed photography, Particle Dynamics Analyzers (PDA), and Particle Image Velocimetry (PIV). The photoelectric cells, high-speed photography, and PDA methods are useful in studying the velocity distribution of particles. In contrast, PIV is a whole-flow-field technique that permits studies of the average velocity field within a target area. The methods provided similar results in some cases, but considerable differences also existed. They provide similar conclusions about the overall velocity distributions at a specific height, but direct measurements of the velocity distribution close to the surface are scarce, except for some PDA results. The magnitude of the measured mean particle velocity also differed greatly among the methods, as did the relationship between mean particle velocity and wind velocity, particle size, and possibly other influencing factors. Although several authors have proposed similar power functions to describe the variation in mean particle velocity with height, the results predicted by these models differed widely. Each technique is based on unique principles, and has related advantages and disadvantages. To make full use of the different techniques, more work must be done to validate the methods and develop a reliable technique for measuring the velocity of blowing particles.

Key words: aeolian transport, velocity of particles, measurement techniques

中图分类号:

O368:P931.3

董治宝;钱广强;罗万银;王洪涛. 几种常用风沙颗粒测速方法对比[J]. 中国沙漠, 2010, 30(4): 749-757.

DONG Zhi-bao;QIAN Guang-qiang;LUO Wan-yin;WANG Hong-tao. Measuring the Velocity of Particles in an Aeolian Saltation Cloud: A comparison of several commonly used methods[J]. JOURNAL OF DESERT RESEARCH, 2010, 30(4): 749-757.

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