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| Titel |
Effects of Grain Size Distributions on Fluid-Sediment Feedback |
| VerfasserIn |
Daniel Conley, Daniel Buscombe |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250044435
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| Zusammenfassung |
| Accounting for the feedback effects between sediment suspension and the generation of
turbulence (Conley et al., 2008) has recently been shown to improve predictions of
morphological evolution (Falchetti et al. 2010). Accounting for these interactions,
which in general lead to an increase in the wave coherent component of transport
relative to the mean component of transport, have been shown to even result in
a change of transport direction. However most research to date has focused on
simulations representing the unrealistic case of sediment beds composed of a single grain
size.
The recently initiated project TSSAR Waves (Turbulence, Sediment Stratification and Altered
Resuspension under Waves) has initially focused on examining how the size distribution of
bed sediments affects this fluid-sediment feedback. It has already been demonstrated (Conley
et al. 2008) that the magnitude of the effects of sediment stratification scale with the ratio of
maximum orbital velocity to grain settling velocity suggesting that the effects will be
highly dependent on the grain size distribution. The nature of these effects has been
investigated utilizing a modified version of the Generalized Ocean Turbulence Model
(GOTM).
Implementation of the ability to handle size distributions involved investigating questions
such as how the mobility of individual scaseize fractions are related to total bed mobility, how
excess shear stress is partitioned among size classes and grain size dependency of the
Schmidt number. Observations from these investigations will be presented as well as
predictions of sediment mobilization and suspension which are compared to appropriate
laboratory experiments.
Reference:
Conley, D.C., Falchetti, S., Lohmann, I.P., Brocchini, M. (2008) The effects of flow
stratification by non-cohesive sediment on transport in high-energy wave-driven flows. J.
Fluid Mech., 610, 43-67.
Falchetti, S., Conley, D.C., Brocchini, M. Elgar, S. (2010), Nearshore bar migration and
sediment induced buoyancy effects. Continental Shelf Res., n. 2, v. 30, 226-238. |
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