Barchan ripples under unidirectional water flows in the laboratory: formation and planar morphology
Barchan ripples under unidirectional water flows in the laboratory: formation and planar morphology
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DOI：
10.1002/esp.1227
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发表时间：
2005-12
影响因子：
3.3
通讯作者：
N. Endo;T. Sunamura;H. Takimoto
中科院分区：
文献类型：
--
作者：
N. Endo;T. Sunamura;H. Takimoto
本研究的目的是研究实验室单向水流产生的新月形波纹的形成和平面形状，并与自然环境中实验室波浪和水流形成的新月形波纹的形态进行比较。一个薄单板的沙作为沉积物源最初被放置在上游部分的循环水槽和床配置的变化，由流动被摄像机记录。观察到两种类型的形成过程：一种是新月形波纹生长于新月形底形，另一种是它们发展于一个小的沙粒集合体。本试验中的新月形波纹在高度-宽度关系和迁移速度方面具有与先前在沙漠环境和波浪水槽研究中报道的相同的特征。对新月形的平面形状的检查导致的结果是，与实验室中的水波和自然沙漠中的气流形成的新月形相比，新月形波纹具有更大的体长/宽度值。新月形波纹的角长/宽小于沙漠中新月形沙丘的角长/宽，但大于振荡实验室流中新月形沙丘的角长/宽。版权所有© 2005年约翰威利父子有限公司。
The purpose of the present study is to investigate the formation and planar shape of barchan ripples generated by laboratory unidirectional water currents and to compare the morphology with that of barchans formed by laboratory waves and flows in natural environments. A thin veneer of sand as a sediment source was placed initially at the upstream part of a recirculating flume and the change in bed configurations by the flow was recorded by a video camera. Two types of formative process were observed: one was that barchan ripples grew from barchanoid bedforms and the other was that they developed from a small aggregate of sand particles. The barchan ripples in the present test had the same characteristics in the height–width relation and in the migration speed as previously reported from the desert environment and wave‐flume studies. An examination of the planar shape of the barchans led to the result that the barchan ripples had larger values of body‐length/width, compared with those of barchans formed by water waves in the laboratory and by airflow in natural deserts. The horn‐length/width of the barchan ripples was smaller than that of barchan dunes in deserts but larger than that of barchans in oscillatory laboratory flows. Copyright © 2005 John Wiley & Sons, Ltd.