21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-3.10.5

BOUNDARY LAYER EFFECTS ON THE BASE PRESSURE BEHIND A BLUNT TRAILING EDGE AEROFOIL

Vassilopoulos K., Gai S. L.
University of New South Wales, Australia

Keywords: boundary layer, base pressure, blunt trailing edge aerofoil

The nature of the boundary layer at the point of separation from a plain blunt trailing edge aerofoil was examined to determine its effect on the base pressure in the near wake. Tests were conducted in a low turbulence subsonic wind tunnel, with and without end plates. The results show that with a laminar boundary layer and end plates, the region of nominally two dimensional vortex shedding was more than doubled. The turbulent boundary layer reduces the mean base pressure coefficient, but unlike the laminar boundary layer, does-not extend the region of nominally two dimensional flow. The fluctuating pressure signals suggest that the turbulent boundary layer also improves the two dimensionality of the shedding vortex street as evidenced by the significantly larger, well correlated, pressure fluctuations.

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