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Electrification of saltating particles in wind‐blown sand: Experiment and theory
Author(s) -
Zhang Huan,
Zheng XiaoJing,
Bo Tianli
Publication year - 2013
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2013jd020239
Subject(s) - triboelectric effect , faraday cup , mass ratio , mechanics , electric charge , materials science , wind tunnel , physics , composite material , optics , beam (structure) , quantum mechanics , astrophysics , ion beam
The electrification of sand particles is a common phenomenon in wind‐blown sand movement. The charge‐to‐mass ratio of particles is an important parameter to characterize the property of charged particles. However, understanding of the charge‐to‐mass ratio remains open, and significant discrepancies exist between previous contact electrification models and measurements. This work focuses on the charge‐to‐mass ratio of saltating particles in wind‐blown sand. Experiments were carried out in a wind tunnel using sand particles with the mean diameterd ¯ = 160 µm . The motions of the saltating particles in the air flow were analyzed by particle image velocimetry, and the charge‐to‐mass ratios were determined by measuring both the charge and mass of saltating sand particles collected in a Faraday cup. The measured results show that the charge‐to‐mass ratio increases exponentially with the height above the surface and the vertical profiles of the charge‐to‐mass ratios can be reproduced well by considering the multiple collisions process between saltating particles and sand bed. In addition, the results suggest that the charge‐to‐mass ratio is determined by the number of collisions, impacting velocity, and sand grain diameter combined.