HR: 1330h
AN: H33A-04    [Abstracts]
TI: A Conceptual Physical Model of Jet Current Turbulence in the Mouth of a River Inflowing Into a Nontidal Enclosed Sea
AU: * Khanbilvardi, R M
EM: rk@ce.ccny.cuny.edu
AF: International Center for Environmental Research and Development, 140th St. at Convent Ave. Steinman Hall, T-105, City College of City University of New York, New York, NY 10021 United States
AU: Shteinman, B
EM: b_shtein@access4less.net
AF: International Center for Environmental Research and Development, 140th St. at Convent Ave. Steinman Hall, T-105, City College of City University of New York, New York, NY 10021 United States
AU: Ozkurt, O
EM: ozlen5@yahoo.com
AF: The Graduate Center and University Center of the City University of New York, 365 Fifth Ave., New York, NY 10016 United States
AB: The results of measurements performed in multiple river mouths, as well as theoretical analysis, have led to revealing a number of special features of mouth currents. This made it possible to formulate a conceptual physical model of free jet current turbulence in the mouth of a river inflowing into a nontidal enclosed sea. Its main principles are as follows: The structure of turbulence is characterized by the presence of a hierarchy of energy supply zones in the velocity spectra. The energy spectra have two basic discrete zones of energy supply, which are related: the first to the hydrodynamic instability of the averaged flow, and the second to the increased friction on the river jet boundaries. These discrete zones are separated by the inertial interval. Moving away from the mouth into the sea (to the bar), the ordinates of the spectral density are decreasing and the zones of additional energy supply move into the domain of higher frequencies. In all sections of the jet flow within the river mouth, the generation of turbulent energy exceeds its dissipation. This excess increases along the jet flow. In all sections, dissipation and generation of turbulent energy increase from the surface to the bottom. The dissipation of energy decreases in the section before the bar, while beyond the bar it rises along the flow, due to the increasing hydraulic resistance at the bar. The longitudinal dimensions of turbulent eddies get smaller with the distance from the mouth gauge, while their orientation is changing from the predominantly vertical-longitudinal rotation over a horizontal axis to the predominantly horizontal-transversal rotation over a vertical axis. With the advance of the river jet from the mouth into the sea, the predominance of the longitudinal dimensions of the eddies changes to the predominance of their transversal dimensions. The farther from the mouth, in the spectra of the river jet current there appear frequency intervals that can be described not by the known Kolmogorov's "-5/3" law but by the "-7/3" law. This feature is due to the increasing friction on the side boundaries of the jet. As the river jet moves beyond the mouth bar, another frequency interval appears in the energy spectra; it can be described by the "-3" law. This is attributed to the consumption of energy by the river jet flow for overcoming the ascending forces when the process of vertical mixing of river and sea water masses is going on beyond the bar.
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: 2005 Joint Assembly