21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.5.1

REATTACHMENT OF AN INCLINED WALL JET

Lai J. C. S., Lu D.
University of New South Wales, Australia

Keywords: reattachment, inclined wall jet

Despite numerous theoretical and experimental studies of wall jets, the velocity field of an inclined wall jet in the near field has never been fully explored. The complex flow features of an inclined wall jet include the outer and inner shear layers of the jet and the recirculation flow region bounded by the nozzle plate, the wall and the inner shear layer. In this paper, these flow features are illustrated by laser sheet smoke flow visualisation and quantified by hot-wire and LDA measurements for a 30° inclined wall jet with a nozzle exit Reynolds number of 6,700. Comparisons between the hot-wire and LDA measurements indicate that except in the recirculation flow region where hot-wires cannot discriminate against reversed flow, the results are very similar. Reattachment lengths determined by LDA for various inclined wall angles indicate that provided that the nozzle aspect ratio is greater than 30 and ~ is less than 50°, the reattachment length is independent of the nozzle aspect ratio and the nozzle exit Reynolds number between 6,670 and 13,340. These reattachment lengths determined by LDA show general agreement with those determined using wall surface oil film visualisation technique.

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