The Importance of Dunes on a Variety of Planetary Surfaces

Titus, T. N.; Zimbelman, J. R.; Radebaugh, Jani

doi:10.1029/2015eo034201

Cited by 2 publications

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“…While the transport of erodible sand or gravel is a function of instantaneous forces or their time integrated effect (impulse), the development of bedforms affects the spatial distribution of such forces, feeding back into the potential for further erosion to take place [2,3]. Dunes are observed, and are deemed of significance to the dynamics of near-surface boundary layers in various planetary environments [4]. As a consequence, there have been extensive field studies of flow over such features in aeolian [5,6] and fluvial or marine environments [7][8][9][10] as well as many experimental studies [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of the velocity-intermittency structure for flow over a field of symmetric dunes

2016

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Owing to their frequent occurrence in the natural environment, there has been significant interest in refining our understanding of flow over dunes and other bedforms. Recent work in this area has focused, in particular, on their shear layer characteristics and the manner by which flow structures are generated. However, field-based studies, are reliant on single-, or multi-point measurements, rather than delimiting flow structures from the velocity gradient tensor as is possible in numerical work. Here, we extract pointwise time series from a well-resolved large-eddy simulation as a means to connect these two approaches. The at-a-point analysis technique is termed the velocityintermittency quadrant method and relates the fluctuating, longitudinal velocity, u ′ 1 (t), to its fluctuating pointwise Hölder regularity, α ′ 1 (t).Despite the difference in boundary conditions, our results agree very well with previous experiments that show the importance, in the region above the dunes, of a quadrant 3 (uflow configuration. Our higher density of sampling beneath the shear layer and close to the bedforms relative to past experimental work reveals a negative correlation between u ′ 1 (t) and α

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Section: Introductionmentioning

confidence: 99%

Large eddy simulation of the velocity-intermittency structure for flow over a field of symmetric dunes

2016

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“…Special issues for earlier dunes workshops in this series were summarized by Bourke et al (2010), Zimbelman et al (2013), andZimbelman (2014). A brief summary of some of the topics covered at the 2015 workshop were also reported by Titus et al (2015). These highly productive workshops would not be possible without the hard work and dedication of the conference convener, Timothy Titus, the other science organizing committee members (Joshua Bandfield, Mary Bourke, Lori Fenton, Rosalyn Hayward, Briony Horgan, Jani Radebaugh and James Zimbelman), session chairs, and workshop attendees.…”

Section: Introductionmentioning

confidence: 99%