A stochastic model for initial movement of sand grains by wind |
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| Authors: | Zhen‐shan Li Xiao‐hu Zhao Wen Huang |
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| Institution: | 1. Department of Environmental Engineering, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Peking University, China;2. Institute for Nanobiomedical Technology and Membrane Biology, State Key Laboratory of Biotherapy of Human Diseases, Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, China |
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| Abstract: | A stochastic model for entrainment of sand grains by wind is presented through analysis of the forces exerted on a single spherical grain, coupled with fluctuations of wind velocity and the change in grain position on the surface. The structure of the stochastic model is consistent with experimental data in the literature. The probability of initial motion increases first, and then decreases, with grain size. It reaches a maximum at diameters of about 0·9 mm. Some sand grains are still in motion at less than the conventional threshold velocity, even at very low velocities. The probability of sand grain movement reaches unity at twice the conventional threshold velocity. Considerable discrepancies amongst conventional threshold formulae may result from the different probabilities of initial movement implied in these formulae. Copyright © 2008 John Wiley & Sons, Ltd. |
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| Keywords: | stochastic model threshold velocity initial motion probability |
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