Author(s): Michela De Dominicis
Linked Author(s):
Keywords: Rotating flow; Buoyant coastal current; Turntable experiments; Image processing
Abstract: The purpose of the present study was to explore, by using an idealized laboratory model, what happens when a freshwater coastal oceanic current encounters abrupt changes in the coastline and bathymetry. Every coastline has abrupt topographic features, and it is precisely at these locations where the pathways of buoyant coastal currents are altered and the fate of freshwater is most likely determined. The attention of the present research has been focused on a simple channel that crosscuts a uniform alongshelf topography. The dominant dynamics of the buoyant current negotiating the channel have been analyzed. In particular, the quantity of buoyant water that enters the channel and the amount that passes by have been determined. The study was focused on how the channel width, the buoyant current properties, the channel topography and the bottom slope can affect the current behaviours. To achieve the objectives, a laboratory experimental model, utilizing a tank placed on a rotating table, was used in order to simulate earth’s rotation effects on fluids. The ratio of buoyant flux into the channel to the buoyant flux passing the channel was determined for various values of the nondimensional parameter W/Rd, where W is the width of the channel and Rd is the Rossby radius of deformation. Furthermore, by using an advanced particle tracking software the velocity field of the flow was reconstructed and the temporal evolution of the flow rates analyzed.
Year: 2007