Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunes
Abstract A coherent Doppler profiler was used to measure coincident time series of velocity (u,w), sediment mass concentration (c), and sediment grain size (d), above mobile sand dunes in unidirectional flow (∼1 m/s, ∼1 m water depth). The measurements are used to extract statistical distributions o...
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Wiley
2016-06-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2016GL069579 |
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| author | G. W. Wilson A. E. Hay |
| author_facet | G. W. Wilson A. E. Hay |
| author_sort | G. W. Wilson |
| collection | DOAJ |
| description | Abstract A coherent Doppler profiler was used to measure coincident time series of velocity (u,w), sediment mass concentration (c), and sediment grain size (d), above mobile sand dunes in unidirectional flow (∼1 m/s, ∼1 m water depth). The measurements are used to extract statistical distributions of sediment concentration and flux just above the bed. Observed mass fluxes (uc,wc) were well fit by quasi‐exponential distributions, at all positions along the dune profile, similar to previous observations of single‐particle momenta for bed load over flat beds. Observed concentrations of moving particles were well fit by negative‐binomial distributions, also similar to previous observations over flat beds. These probability distributions relate to two recent stochastic theories, previously derived and verified for uniform flow over flat beds. It is hypothesized that these theories may also be used as a local approximation in natural‐scale flows with bed forms. |
| format | Article |
| id | doaj-art-22f0b0e01fac4470b8f705cbc182f4cd |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2016-06-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-22f0b0e01fac4470b8f705cbc182f4cd2025-08-20T01:50:59ZengWileyGeophysical Research Letters0094-82761944-80072016-06-0143126304631210.1002/2016GL069579Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunesG. W. Wilson0A. E. Hay1Department of Oceanography Dalhousie University Halifax Nova Scotia CanadaDepartment of Oceanography Dalhousie University Halifax Nova Scotia CanadaAbstract A coherent Doppler profiler was used to measure coincident time series of velocity (u,w), sediment mass concentration (c), and sediment grain size (d), above mobile sand dunes in unidirectional flow (∼1 m/s, ∼1 m water depth). The measurements are used to extract statistical distributions of sediment concentration and flux just above the bed. Observed mass fluxes (uc,wc) were well fit by quasi‐exponential distributions, at all positions along the dune profile, similar to previous observations of single‐particle momenta for bed load over flat beds. Observed concentrations of moving particles were well fit by negative‐binomial distributions, also similar to previous observations over flat beds. These probability distributions relate to two recent stochastic theories, previously derived and verified for uniform flow over flat beds. It is hypothesized that these theories may also be used as a local approximation in natural‐scale flows with bed forms.https://doi.org/10.1002/2016GL069579sediment transportacousticsboundary layergranular gases |
| spellingShingle | G. W. Wilson A. E. Hay Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunes Geophysical Research Letters sediment transport acoustics boundary layer granular gases |
| title | Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunes |
| title_full | Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunes |
| title_fullStr | Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunes |
| title_full_unstemmed | Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunes |
| title_short | Acoustic observations of near‐bed sediment concentration and flux statistics above migrating sand dunes |
| title_sort | acoustic observations of near bed sediment concentration and flux statistics above migrating sand dunes |
| topic | sediment transport acoustics boundary layer granular gases |
| url | https://doi.org/10.1002/2016GL069579 |
| work_keys_str_mv | AT gwwilson acousticobservationsofnearbedsedimentconcentrationandfluxstatisticsabovemigratingsanddunes AT aehay acousticobservationsofnearbedsedimentconcentrationandfluxstatisticsabovemigratingsanddunes |