Numerical simulations of buoyant, gravity-driven coastal plumes are summarized and compared to the inviscid geostrophic theory of Thomas & Linden (2007) and to laboratory studies for plumes owing along a vertical-wall coastline (those of Thomas & Linden (2007) and additional experiments performed at Warwick University). In addition, results of two new laboratory studies with different scales for plumes owing along a more realistic inclined-wall coastline are presented and compared to an extended theoretical model from the geostrophic theory of Thomas & Linden (2007). The theoretical and experimental results for plumes flowing along inclined-wall coastlines are compared to the inclined-wall experimental studies of Avicola & Huq (2002), Whitehead & Chapman (1986) and Lentz & Helfrich (2002), to the inclined-wall scaling theory of Lentz & Helfrich (2002), and to oceanic observations. The lengths, widths and velocities of the buoyant gravity currents are studied. Agreement between the laboratory and numerical experiments, and the geostrophic theories for both vertical-wall and inclined-wall studies is found to depend mainly on one non-dimensional parameter which characterizes the strength of horizontal viscous forces (the horizontal Ekman number). The best agreement between the experiments and the geostrophic theories is found for plumes with low viscous forces. At large values of the horizontal Ekman number, laboratory and numerical experiments depart more significantly from theory (e.g., in the plume propagation velocity). At very low values of the horizontal Ekman number (obtained in the large-scale inclined-wall experimental study only), departures between experiments and theory are observed as well. Agreement between experiments and theory is also found to depend on the steepness of the plumes isopycnal interface for the vertical-wall study, and on the ratio between the isopycnal and coastline slopes for the inclined-wall study.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:560157 |
| Date | January 2011 |
| Creators | Gregorio, Sandy O. |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/47656/ |
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