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Characteristics of small vortices were studied in axisymmetric jets wherein the Kolmogorov scale was approached by progressively decreasing the Reynolds number while still maintaining turbulent flow. A periodic forcing introduced far upstream of the jet nozzle ensured that the jet was turbulent. A vortex eduction tool was developed and applied to the high-pass filtered 2D velocity field in the axial plane of a turbulent jet while varying Re between 140 and 2600. Vortex population, energy, vorticity, and rms (root-mean-square velocity fluctuations) of the high-pass filtered field were measured to elucidate vortex characteristics. The observed population of vortices decreases dramatically at the Kolmogorov scale. The observed increase in vortex population with decreasing vortex size appears to be in accord with the space-filling argument, in that the vortex population in a two-dimensional domain should grow as [R.sup.-2]. The energy density curve obtained from vortex statistics reproduces the -5/3 slope for the inertial subrange, and the highpass filtered field accounts for approximately two-thirds of the total rms. [DOI: 10.1115/1.2173292]

The dynamics of relatively large recirculating gyre, or bulge (anticyclonic buoyant lens) region, occurring in some numerical simulations and in oceanic outflow are identified. The characteristics, evolution, and impact of a recirculating bulge in a coastal buoyant outflow are determined by laboratory experiments.

Laboratory experiments of the coastal buoyant outflow are conducted, on a rotating turntable in relatively deep water to analyze the role of bay geometry on the evolution of the outflow. Results of the study are compared to the Bormans and Garrett hypothesis.

A laboratory experiment investigates the influence of salinity on the characteristics of bubble clouds in varying saline solutions. Bubble clouds were generated with a water jet. Salinity, surface tension, and water temperature were monitored. Measured bubble cloud parameters include the number of bubbles, the void fraction, the penetration depth, and the cloud shape. The number of large (above 0.5 mm diameter) bubbles within a cloud increases by a factor of three from fresh to saline water of 20 psu (practical salinity units), and attains a maximum value for salinity of 12-25 psu. The void fraction also has maximum value in the range 12-25 psu. The results thus show that both the number of bubbles and the void fraction vary nonmonotonically with increasing salinity. The lateral shape of the bubble cloud does not change with increasing salinity; however, the lowest point of the cloud penetrates deeper as smaller bubbles are generated. [ABSTRACT FROM AUTHOR]