A Surface Model for Aeolian Dune Topography
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A Surface Model for Aeolian Dune Topography Travis Swanson1 · David Mohrig1 · Gary Kocurek1 · Man Liang1
Received: 12 August 2015 / Accepted: 23 August 2016 © International Association for Mathematical Geosciences 2016
Abstract A surface model for aeolian bedform topography is adapted from a surface model of subaqueous bedform topography. The aeolian bedform surface model is developed using a uniform grid with a cell-centered finite volume approximation of the sediment continuity equation. The resulting modeling framework approximates the dynamic motions of aeolian bedform topography driven by bedform field boundary conditions. The numerical model is applied to simulate bedforms growing from unimodal and bimodal transport regimes from both a fixed elevation (sediment source area) and within a domain with fully periodic boundary conditions. The rates at which modeled aeolian bedforms grow and morphologically mature are sensitive to the chosen boundary conditions. Video files of model simulations and source code for the presented aeolian bedform surface modeling framework are available in supplemental materials. The aeolian bedform surface model code is malleable and readily modified for exploratory study of dynamic bedform topography that inherits morphological traits from aeolian bedform field boundary conditions. Keywords Aeolian · Dune · Bedform · Exploratory numerical model
Electronic supplementary material The online version of this article (doi:10.1007/s11004-016-9654-x) contains supplementary material, which is available to authorized users.
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Travis Swanson [email protected] Department of Geosciences, Jackson School of Geosciences, The University of Texas at Austin, 2305 Speedway, Stop C1160, Austin, TX 78712-1692, USA
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Math Geosci
1 Introduction In this study, a surface model of aeolian topography is developed and applied to approximate aeolian dune growth in several cases, which represent different hypothetical bedform fields subjected to different boundary conditions. A bedform surface model approximates the dynamic motion of the bedform surface, but does not resolve the fluid flow field above the bed surface, or the sedimentary record below. The aeolian surface model developed here is a modification of the bedform surface model presented by Jerolmack and Mohrig (2005). The original surface model casts the dynamic motion of subaqueous dune topography driven by unidirectional flow as a nonlinear relationship between sediment flux and bedform topography, subject to stochastic variability. The surface model for aeolian bedforms is created by implementing two principle modifications to the original model. First, the surface evolution equation is discretized in two dimensions. Therefore, sediment transport can occur in any azimuth direction. Second, sediment elevation can be prescribed along a side of the rectangular domain which is useful to simulate bedform growth from a specified region. This modification describes the influence of a spatially restricted sediment source area, for examp
