Research Group

Experimental setup for shallow tidal flow through an inlet in a barrier island.

Francisco Nicolau del Roure

Master of Science. Completed, August, 2007.

Francisco Nicolau del Roure conducted experiments in shallow tidal inlets to characterize the large-scale (many times the water depth) starting jet vortices that form each tidal cycle.

The experiments were conducted at the Institute for Hydromechanics at the University of Karlsruhe, and included both dye visualization and surface particle image velocimetry (PIV). The PIV images were processed using the Matlab MPIV toolbox.

A major component of the research also involved identification and characterization of the starting jet vortices using the PIV data. These coherent structures were identified using the swirling strength (Adrian et al., Exp. Fluids, 2000). Characteristics were then measured over time for the vortex diameter, location, maximum vorticity, circulation, and up-welling potential. Based on these data, there is a rapid and energetic formation stage while the vortex is attached to the inlet. It then becomes entrained in the tidal jet, which initiates the slow decay period due to bottom friction. The characteristic time-scale for vortex attachment and formation was found to be tU/W = 2, where t is the time, U is the maximum velocity through the inlet over one tidal cycle and W is the inlet width.

Publications

  • Nicolau del Roure, F., Socolofsky, S. A., & Chang, K.-A. (2009), "Structure and evolution of tidal starting jet vorties at idealized barotropic inlets." J. Geophys. Res., 114, C05024, doi: 10.1029/2008JC004997.