Handle URI:
http://hdl.handle.net/10754/597975
Title:
Diffusive boundary layers over varying topography
Authors:
Dell, R. W. ( 0000-0002-6886-8952 ) ; Pratt, L. J.
Abstract:
Diffusive bottom boundary layers can produce upslope flows in a stratified fluid. Accumulating observations suggest that these boundary layers may drive upwelling and mixing in mid-ocean ridge flank canyons. However, most studies of diffusive bottom boundary layers to date have concentrated on constant bottom slopes. We present a study of how diffusive boundary layers interact with various idealized topography, such as changes in bottom slope, slopes with corrugations and isolated sills. We use linear theory and numerical simulations in the regional ocean modeling system (ROMS) model to show changes in bottom slope can cause convergences and divergences within the boundary layer, in turn causing fluid exchanges that reach far into the overlying fluid and alter stratification far from the bottom. We also identify several different regimes of boundary-layer behaviour for topography with oceanographically relevant size and shape, including reversing flows and overflows, and we develop a simple theory that predicts the regime boundaries, including what topographies will generate overflows. As observations also suggest there may be overflows in deep canyons where the flow passes over isolated bumps and sills, this parameter range may be particularly significant for understanding the role of boundary layers in the deep ocean.
Citation:
Dell RW, Pratt LJ (2015) Diffusive boundary layers over varying topography. Journal of Fluid Mechanics 769: 635–653. Available: http://dx.doi.org/10.1017/jfm.2015.88.
Publisher:
Cambridge University Press (CUP)
Journal:
Journal of Fluid Mechanics
Issue Date:
25-Mar-2015
DOI:
10.1017/jfm.2015.88
Type:
Article
ISSN:
0022-1120; 1469-7645
Sponsors:
The authors gratefully acknowledge the insightful suggestions of R. Ferrari, T. Peacock, A. Thurnherr and J. Toole, as well as the anonymous reviewers. Partial support for this work was provided by the National Science Foundation through OCE0927017, OCE 1357078, OCE 0927017 and their Graduate Research Fellowship Program. Partial support was also provided by KAUST and the WHOI Deep Ocean Exploration Institute.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorDell, R. W.en
dc.contributor.authorPratt, L. J.en
dc.date.accessioned2016-02-25T13:10:11Zen
dc.date.available2016-02-25T13:10:11Zen
dc.date.issued2015-03-25en
dc.identifier.citationDell RW, Pratt LJ (2015) Diffusive boundary layers over varying topography. Journal of Fluid Mechanics 769: 635–653. Available: http://dx.doi.org/10.1017/jfm.2015.88.en
dc.identifier.issn0022-1120en
dc.identifier.issn1469-7645en
dc.identifier.doi10.1017/jfm.2015.88en
dc.identifier.urihttp://hdl.handle.net/10754/597975en
dc.description.abstractDiffusive bottom boundary layers can produce upslope flows in a stratified fluid. Accumulating observations suggest that these boundary layers may drive upwelling and mixing in mid-ocean ridge flank canyons. However, most studies of diffusive bottom boundary layers to date have concentrated on constant bottom slopes. We present a study of how diffusive boundary layers interact with various idealized topography, such as changes in bottom slope, slopes with corrugations and isolated sills. We use linear theory and numerical simulations in the regional ocean modeling system (ROMS) model to show changes in bottom slope can cause convergences and divergences within the boundary layer, in turn causing fluid exchanges that reach far into the overlying fluid and alter stratification far from the bottom. We also identify several different regimes of boundary-layer behaviour for topography with oceanographically relevant size and shape, including reversing flows and overflows, and we develop a simple theory that predicts the regime boundaries, including what topographies will generate overflows. As observations also suggest there may be overflows in deep canyons where the flow passes over isolated bumps and sills, this parameter range may be particularly significant for understanding the role of boundary layers in the deep ocean.en
dc.description.sponsorshipThe authors gratefully acknowledge the insightful suggestions of R. Ferrari, T. Peacock, A. Thurnherr and J. Toole, as well as the anonymous reviewers. Partial support for this work was provided by the National Science Foundation through OCE0927017, OCE 1357078, OCE 0927017 and their Graduate Research Fellowship Program. Partial support was also provided by KAUST and the WHOI Deep Ocean Exploration Institute.en
dc.publisherCambridge University Press (CUP)en
dc.titleDiffusive boundary layers over varying topographyen
dc.typeArticleen
dc.identifier.journalJournal of Fluid Mechanicsen
dc.contributor.institutionClimate, Atmospheric Science, and Physical Oceanography, Scripps Institution of Oceanography, UC – San Diego, San Diego, CA 92093, USAen
dc.contributor.institutionDepartment of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USAen
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