Abstract
A wind-tunnel flutter test on a supercritical wing model is described. Objectives of the test were to investigate the transonic dip and to make comparisons with calculated flutter characteristics in which a quasi-threedimensional transonic theory was used. The beginning of a transonic dip was measured and a satisfactory agreement with theory could be found. An additional flutter instability in the bottom of the transonic dip could be correlated with the loss of transition strip effectivity at low Reynolds numbers. Nomenclature a,b = correction factors [Eqs. (2)] c =chord Clo = sectional steady lift coefficient CL - wing lift coefficient / = frequency g = damping coefficient k = reduced frequency (related to semichord) k - sectional unsteady lift coefficient, k2D, k3D m = sectional unsteady moment coefficient (related to quarterchord), m2D, m3D MO, = Mach number P0 = stagnation pressure q = generalized coordinate Rec = Reynolds number related to mean aerodynamic chord xt = position of transition strip a = wing angle of incidence A = (mean) sweep angle
Published Version
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