Buoyant gravity currents along a sloping bottom in a rotating fluid
Lentz, Steven J.
Helfrich, Karl R.
MetadataShow full item record
The dynamics of buoyant gravity currents in a rotating reference frame is a classical problem relevant to geophysical applications such as river water entering the ocean. However, existing scaling theories are limited to currents propagating along a vertical wall, a situation almost never realized in the ocean. A scaling theory is proposed for the structure (width and depth), nose speed and flow field characteristics of buoyant gravity currents over a sloping bottom as functions of the gravity current transport Q, density anomaly g[prime prime or minute], Coriolis frequency f, and bottom slope [alpha]. The nose propagation speed is cp [similar] cw/ (1 + cw/c[alpha]) and the width of the buoyant gravity current is Wp [similar] cw/ f(1 + cw/c[alpha]), where cw = (2Qg[prime prime or minute] f)1/4 is the nose propagation speed in the vertical wall limit (steep bottom slope) and c[alpha] = [alpha]g/f is the nose propagation speed in the slope-controlled limit (small bottom slope). The key non-dimensional parameter is cw/c[alpha], which indicates whether the bottom slope is steep enough to be considered a vertical wall (cw/c[alpha] [rightward arrow] 0) or approaches the slope-controlled limit (cw/c[alpha] [rightward arrow] [infty infinity]). The scaling theory compares well against a new set of laboratory experiments which span steep to gentle bottom slopes (cw/c[alpha] = 0.11–13.1). Additionally, previous laboratory and numerical model results are reanalysed and shown to support the proposed scaling theory.
Author Posting. © Cambridge University Press, 2002. This article is posted here by permission of Cambridge University Press for personal use, not for redistribution. The definitive version was published in Journal of Fluid Mechanics 464 (2002): 251-278, doi:10.1017/S0022112002008868.
Showing items related by title, author, creator and subject.
Nonlinear adjustment of a localized layer of buoyant, uniform potential vorticity fluid against a vertical wall Helfrich, Karl R. (2006-01-29)The nonlinear evolution of a localized layer of buoyant, uniform potential vorticity fluid of uniform depth H, width w0 and length L released adjacent to a wall in a rotating system is studied using reduced-gravity ...
Seasonal variation of ocean bottom pressure derived from Gravity Recovery and Climate Experiment (GRACE) : local validation and global patterns Kanzow, Torsten; Flechtner, Frank; Chave, Alan D.; Schmidt, Roland; Schwintzer, Peter; Send, Uwe (American Geophysical Union, 2005-09-02)The Gravity Recovery and Climate Experiment (GRACE) processing centers at the GeoForschungsZentrum Potsdam (GFZ) and the University of Texas Center for Space Research (UTCSR) provide time series of monthly gravity field ...
Laboratory experiments on the interaction of a buoyant coastal current with a canyon : application to the East Greenland Current Sutherland, David A.; Cenedese, Claudia (American Meteorological Society, 2009-05)This paper presents a set of laboratory experiments focused on how a buoyant coastal current flowing over a sloping bottom interacts with a canyon and what controls the separation, if any, of the current from the upstream ...