Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
An experimental measurements of unsteady wakes behind a
sinusoidally plunging airfoil was surveyed with a Hot-wire
rake containing seven I-wires. The aim of these
measurements was to study the velocity profiles behind the
oscillating airfoil trailing edge. Influences of reduced
frequency and angle of attack were studied in details. It was
shown that the angle of attack and reduced frequency are
the most important parameters which influence on the
velocity profiles. The momentum deficit was relative to
reduced frequency and amplitude of oscillation and its
behaviours were changed after static stall angles. At the
angle of attack beyond static stall angle flow separation
causes increasing the momentum deficit. The velocity
profile has approximately symmetric shape profile.
Data were taken at mean incidence angles of 0, 8 degrees at
reduced frequencies of 0.09 to 0.56. The nondimensional
amplitude of oscillation was 0.27. The corresponding
Reynolds numbers, based on the chord length, were 25000
and 150000.
