Author(s): Valentina Dore
Linked Author(s):
Keywords: Buoyant Coastal Current; Coastal Pollution; Dispersion; Harmful Algal Blooms; Interaction; Mixing; Density Measurements; PLIF; Image Processing
Abstract: Buoyant coastal currents transport fresh water, heat, nutrients, sediments, pollutants, and biological organism along the coasts of continents all over the world. Such currents thus significantly impact ecosystems, climate conditions, coastal circulation and coastal communities. The manner in which buoyant plumes interact alongshore will influence coastal distribution of materials contained in individual plumes. The current experimental study, conducted both at the Geophysical Fluid Dynamics Laboratory at the Woods Hole Oceanographic Institution (W. H. O. I, Woods Hole, MA, USA) and at the Hydraulics Laboratory of D. I. T. S. (University “La Sapienza”, Rome), investigates, through an idealized laboratory model, the interaction of two buoyant coastal currents having different densities and flow rates, in a rotating reference frame. Our interest focus in general on the classification of all the probable scenarios generated by the interaction of the two plumes, in order to determine how the water masses of individual plumes are distributed in space and time as a function of buoyancy flux and bottom slope. Two experimental configurations were set up, modelling respectively two surface trapped plumes (vertical wall configuration) and two slope controlled plumes (sloping bottom configuration). The amount of mixing, for both the arrangements, is quantified in two ways: by using density observations and by combining the Planar Laser Induced Fluorescence (PLIF) with digital imaging and processing. Considering the hypothesis that only the upward plume is polluted, the major scientific interest focus on the estimation of the quality of water downward, along the coastline at shallow depth, that is the area where the societal and ecological value is greater.
Year: 2007