Interaction of a two-phase turbulent/bubbly submerged water jet with a single-phase jet: Measurements of the enhanced hydrodynamic near-field spectrum, part II

Abstract

The interaction of mutually perpendicular submerged turbulent water jets is studied from measurements of the hydrodynamic near-field pressure spectrum. One jet is a conventional single-phase, free turbulent shear flow circular jet, while the other jet is a two-phase bubbly jet of similar construction. The overlap region is located at four nozzle diameters (4D) away from each orifice. A small hydrophone located outside the overlap region on the symmetry line 45° from each jet axis (and in the far quadrant from each nozzle exit) measures the near-field pressure signature. Spectra are measured at different radial positions from the overlap region (typically 4D–10D). Very small gas bubbles are generated in the two−phase turbulent jet by pressurized N2 gas passing through a fritted disk housed in a Buchner funnel located near the nozzle entrance. Spectra are compared for different void fractions and different Reynolds numbers (based on jet diameter). Typically, volume void fractions ∼0.001 significantly amplify the flow noise coming from jet nozzles (D=0.635 cm) with nozzle exit velocities of 10 m/s. [See earlier work, J. Acoust. Soc. Am. 102, 3184(A) (1997).] [Work supported by the Naval Acad. Res. Council.]