DOI: 10.1002/2017JF004462
Scopus记录号: 2-s2.0-85046608783
论文题名: Controls on Yardang Development and Morphology: 2. Numerical Modeling
作者: Pelletier J.D.
刊名: Journal of Geophysical Research: Earth Surface
ISSN: 21699003
出版年: 2018
卷: 123, 期: 4 起始页码: 723
结束页码: 743
语种: 英语
英文关键词: abrasion
; drag
; numerical modeling
; yardangs
Scopus关键词: abrasion
; drag
; geomorphology
; landscape evolution
; numerical model
; sediment transport
; topography
; wind erosion
英文摘要: Here I present a set of mathematical modeling results, constrained by the results of the companion paper, aimed at improving our understanding of yardang development and controls on yardang morphology. The classic model for yardang development posits that yardangs evolve to an aspect ratio of ≈4 in order to minimize aerodynamic drag. Computational fluid dynamics model results presented here, however, demonstrate that yardangs with an aspect ratio of 4 do not minimize drag. As an alternative, I propose that yardang aspect ratios are primarily controlled by the lateral downwind expansion of wind and wind-blown sediments focused into the troughs among yardangs, which can be quantified using previous studies of wall-bounded turbulent jets. This approach predicts yardangs with aspect ratios in the range of 5 to 10, that is, similar to those of natural yardangs. In addition to aerodynamics, yardang aspect ratios are influenced by the strikes and dips of strata, as demonstrated in the companion paper. To better understand the aerodynamic and bedrock structural controls on yardang morphology, I developed a landscape evolution model that combines the physics of boundary layer flow and abrasion by eolian sediment transport with a model for the erosion of the tops and lee sides of yardangs by water-driven erosional processes. Yardang formation in the model is enhanced in substrates with greater heterogeneity (i.e., alternating strong and weak strata). Yardang morphology is controlled by the strikes and dips of strata as well as the topographic diffusivity associated with water-driven erosional processes. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/114115
Appears in Collections: 气候减缓与适应
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作者单位: Department of Geosciences, University of Arizona, Tucson, AZ, United States
Recommended Citation:
Pelletier J.D.. Controls on Yardang Development and Morphology: 2. Numerical Modeling[J]. Journal of Geophysical Research: Earth Surface,2018-01-01,123(4)