An experiment in a wind tunnel was conducted to record the evolution of downsized dunes from both top and side view by using an optical test system. The results show that downsized dunes gradually developed into barchans with sand supply given by the wind erosion on a sand bed. A further analysis on the profile variation indicates that the dunes erosion occurred mainly on the leeward side
and the erosion increased with the decrease in the ratio of the dune width and height. However
on the windward side
the erosion only occurred at the initial stage of the evolution and subsequently remained nearly unchanged. The erosion rate approached a nonzero constant on the leeward side while zero on the windward side as time went on. In addition
the relevance analysis on the dune width and height shows a clear monotonic relationship between dune erosion and the ratio of the dune width and height
so the ratio can be used as an independent parameter to describe the evolution of dunes.
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references
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