near free-surface region Experimental study of the flow structure in the

calculated from the data collected. kinetic energy distribution. Velocity spectra and autocorrelations were also velocity fields, mean velocity profiles, turbulence intensities and turbulent Flow visualization and PIV techniques were used to compute instantaneous region of a tank agitated by jets located in the bottom are presented in the paper. Results of an experimental study about the flow structure in the near free surface phenomenon, which is important in the gas transfer process across the interface. upwelling of fluid. It is postulated that these events are associated to the renewal most relevant event corresponds to a horizontal sweep, usually preceded by an periodical pattern, was inferred from flow visualization and measurements. The A succession of events in the near air-water interface, forming a quasi