Experimental study of aeolian sand ripples in a wind tunnel |
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| Authors: | Hong Cheng Chenchen Liu Jifeng Li Bo Liu Zhongquan Zheng Xueyong Zou Liqiang Kang Yi Fang |
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| Institution: | 1. State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China;2. Engineering Center of Desertification and Blown‐Sand Control of Ministry of Education, Faculty of Geographical Science, Beijing Normal University, Beijing, China;3. Beijing Engineering Research Center of Desertification and Blown‐sand Control, Faculty of Geographical Science, Beijing Normal University, Beijing, China;4. School of Resources and Environmental Sciences, Hebei Normal University, Shijiazhuang, China;5. Department of Aerospace Engineering, University of Kansas, Lawrence, KS, USA |
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| Abstract: | The topographic parameters and propagation velocity of aeolian sand ripples reflect complex erosion, transport, and deposition processes of sand on the land surface. In this study, three Nikon cameras located in the windward (0–1 m), middle (4.5–5.5 m), and downwind (9–10 m) zones of a 10 m long sand bed are used to continuously record changes in sand ripples. Based on the data extracted from these images, this study reaches the following conclusions. (1) The initial formation and full development times of sand ripples over a flatbed decrease with wind velocity. (2) The wavelengths of full development sand ripples are approximately twice the wavelengths of initially formed sand ripples. Both wavelengths increase linearly with friction velocity. During the developing stage of sand ripples, the wavelength increases linearly with time. (3) The propagation velocity of full development sand ripples is approximately 0.6 times that of the initially formed sand ripples. The propagation velocity of both initial and full development of sand ripples increase as power functions with respect to friction velocity. During the developing stage of sand ripples, the propagation velocity decreases with time following a power law. These results provide new information for understanding the formation and evolution of aeolian sand ripples and help improve numerical simulations. Copyright © 2017 John Wiley & Sons, Ltd. |
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| Keywords: | aeolian sand ripple propagation velocity wavelength friction velocity wind tunnel |
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