Eolian dunes: Computer simulations and attractor interpretation

Werner, B. T.

doi:10.1130/0091-7613(1995)023<1107:edcsaa>2.3.co;2

Cited by 334 publications

(384 citation statements)

References 4 publications

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“…Thus g > 90°produces longitudinal or oblique bed forms. This result was initially based on experiments in air [Rubin and Hunter, 1987] and water [Rubin and Ikeda, 1990], and has been reproduced in subsequent numerical simulations of bed form development [Werner, 1995;Nishimori et al, 1998;Kocurek and Ewing, 2005].…”

Section: Application Of Mgbnt To Combined Flowsmentioning

confidence: 90%

Bed forms created by simulated waves and currents in a large flume

et al. 2007

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[1] The morphology and evolution of bed forms created by combinations of waves and currents were investigated using an oscillating plate in a 4-m-wide flume. Current speed ranged from 0 to 30 cm/s, maximum oscillatory velocity ranged from 20 to 48 cm/s, oscillation period was 8 s (except for one run with 12 s period), and the median grain size was 0.27 mm. The angle between oscillations and current was 90°, 60°, or 45°. At the end of each run the sand bed was photographed and ripple dimensions were measured. Ripple wavelength was also determined from sonar images collected throughout the runs. Increasing the ratio of current to wave (i.e., oscillatory) velocity decreased ripple height and wavelength, in part because of the increased fluid excursion during the wave period. Increasing the ratio of current to waves, or decreasing the angle between current and waves, increased the three-dimensionality of bed forms. During the runs, ripple wavelength increased by a factor of about 2. The average number of wave periods for evolution of ripple wavelength to 90% of its final value was 184 for two-dimensional ripples starting from a flat bed. Bed form orientations at the end of each run were compared to four potential controlling factors: the directions of waves, current, maximum instantaneous bed shear stress, and maximum gross bed form normal transport (MGBNT). The directions of waves and of MGBNT were equally good predictors of bed form orientations, and were significantly better than the other two factors.

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Section: Application Of Mgbnt To Combined Flowsmentioning

confidence: 90%

Bed forms created by simulated waves and currents in a large flume

et al. 2007

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“…Models suggest that dune fields self-organize into emergent patterns that lead to greater order, dune-dune spacing, and/or overall dune size (e.g., Werner, 1995). The pattern at any given time step reflects the boundary conditions and the constructional time leading up to that point.…”

Section: Examining Controls Of Dune Activitymentioning

confidence: 99%

Remote sensing and spatial analysis of aeolian sand dunes: A review and outlook

Hugenholtz

Levin

Barchyn

et al. 2012

Earth-Science Reviews

177

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“…To date the majority of dune morphological modelling has been performed using cellular automaton (CA) models (Werner, 1995;Bass, 2002). Although CA modelling is effective at creating realistic dune forms under a range of conditions such as wind direction (Zhang et al, 2012) and vegetation (Nield and Baas, 2008), the simple assumptions determining the models outcome cannot yet be used to predict morphological change in reality (Zheng, 2009).…”

Section: Dune Morphological Modellingmentioning

confidence: 99%

Aeolian dynamics of beach scraped ridge and dyke structures

Smyth

Hesp

2015

Coastal Engineering

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Where urban areas are situated close to a beach, sand dunes act as protection from flooding and erosion. When a dune has been removed or damaged by erosion, dune, ridge or dyke re-building using heavy machinery, a process known as beach scraping, is a common method of restoration. Following construction, natural accretion of sediment on the backshore is preferable as it facilitates sustained natural dune building, growth of vegetation, habitat creation and reduces the need for further beach scraping.This study investigates the near surface flow and transport potential for three artificial structure designs: a single ridge, a double ridge and a dyke. The three shapes contained an identical volume of sand and were preceded by 50 m of beach at an angle of 3°. A computational fluid dynamic model (CFD) was created for each scenario to calculate wind flow and shear velocity from 4 different wind directions at 22.5° intervals from 0° (onshore) to 67.5°. From this data sediment flux was predicted along a two dimensional transect for each of the scenarios.For all structures, shear velocity on the beach and stoss slope decreased as incident wind direction became more oblique, conversely shear velocity in the lee of the crest increased. A reduction in shear velocity at the foot of each structure also occurred and appears related to stoss slope, with the reduction greatest reduction at the toe of the dyke structure (stoss slope 34°) and the least before the single ridge (stoss slope 17°).Specifically the results suggest that the double ridge structure is the most resilient to aeolian erosion. Shear velocity reduction on the back beach is comparable to the dyke and sediment flux from the stoss slope of the double ridge structure may become trapped in the swale between the two ridges encouraging sediment deposition, thus reducing sediment transport beyond the dunes and backshore. Although the dyke structure underwent the greatest reduction in shear velocity on the back beach it experienced substantial sediment flux at the crest and along the top of the structure, making it susceptible to erosion during a strong wind event. The highest sediment transport rate was calculated at the crest of the single ridge, and the single ridge structure also created the smallest reduction of shear velocity on the back beach, thus making it less desirable than the double ridge.

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Eolian dunes: Computer simulations and attractor interpretation

Cited by 334 publications

References 4 publications

Bed forms created by simulated waves and currents in a large flume

Bed forms created by simulated waves and currents in a large flume

Remote sensing and spatial analysis of aeolian sand dunes: A review and outlook

Aeolian dynamics of beach scraped ridge and dyke structures

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