22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-3.7.1

NUMERICAL ANALYSIS OF BLOCKAGE EFFECTS IN SLOTTED WIND TUNNEL

G. Lombardi (1), M.V. Salvetti (1), M. Morelli (2)
(1) University of Pisa, Italy; (2) Medium Speed Wind Tunnel, CSIR, South Africa

Keywords: blockage effects, correction methodologies, numerical simulations

A procedure is proposed for the correction of wind tunnel blockage effects on the experimental measurement of aerodynamic coefficients. The correction is obtained as the difference between the values obtained in two different numerical simulations: in the first one the flow over the model in “free-air” conditions is simulated, while, in the second one, the measured pressure values over the wind tunnel walls are used as boundary conditions. A necessary preliminary step is the choice of the number, location and accuracy of the pressure measurements. A strategy is proposed to determine these parameters, based on the same correction procedure in which the experimental part is replaced by numerical simulation. This strategy is applied to the subsonic flow around a complete aircraft configuration by means of a potential flow solver. Preliminary results for transonic flow around a wing section, obtained through a Navier-Stokes solver, are also presented.

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