Degree Name

BS

Department

Physics and Astronomy

College

Physical and Mathematical Sciences

Defense Date

2019-05-21

Publication Date

2019-08-01

First Faculty Advisor

Manuel Berrondo

First Faculty Reader

Jani Radebaugh

Honors Coordinator

Lawrence Rees

Keywords

Nishimori's model, sand ripples, megaripples, saltation, emergence, bifurcation

Abstract

In the interest of drawing conclusions about Aeolian environments based on remote imaging, we investigated how air flow forms self-organizing patterns, such as ripples, across loose particulate surfaces. Specifically, we analyzed various models of sand transport, particularly Nishimori’s model, to note the effects of altering various parameters, including wind direction, saltation length, diffusion, and a saltation proportionality constant. As a measure of the frustration of the emergent patterns, Y-junctions were counted at various values of the parameters. A strong correlation with the saltation proportionality constant and no correlation with the saltation height were found. As an additional use of the model, terrestrial gravel ripples in the Lut Desert, Iran were measured, with an average length of 50.0 m and a right-skewed distribution found. For these gravel ripples, particle movement has a larger dependence on initial height than for smaller, more common sand ripples.

In the interest of drawing conclusions about Aeolian environments based on remote imaging, we investigated how air flow forms self-organizing patterns, such as ripples, across loose particulate surfaces. Specifically, we analyzed various models of sand transport, particularly Nishimori’s model, to note the effects of altering various parameters, including wind direction, saltation length, diffusion, and a saltation proportionality constant. As a measure of the frustration of the emergent patterns, Y-junctions were counted at various values of the parameters. A strong correlation with the saltation proportionality constant and no correlation with the saltation height were found. As an additional use of the model, terrestrial gravel ripples in the Lut Desert, Iran were measured, with an average length of 50.0 m and a right-skewed distribution found. For these gravel ripples, particle movement has a larger dependence on initial height than for smaller, more common sand ripples.

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