Measurement Correction of Two-Dimensional Wind Tunnel with Porous Walls using Singularity Method

The correction method is developed to correct the distribution of pressure coefficient around an airfoil for the aim of the post processing of measurement data from wind tunnel. The measured pressure coefficient is numerically corrected to compensate walls interference effects for wind tunnel test section. The airfoil NACA0012, in this paper, is simulated by segments with linear vortex, which are then mirrored due to the floor and ceiling of the wind tunnel test section using sufficient number of images, to simulate the flow around an airfoil in the test section with walls. The perforated wall is approximated by constant source segments. Flow calculations, both in the free stream and with the presence of tunnel walls, are then performed. The numerically pressure coefficient difference obtained between these two cases should be superimposed to the measured pressure coefficient distribution in the wind tunnel for the same airflow conditions and corresponding points, resulting in the experimental pressure coefficient distribution corrected. With the relative height reduction of the wind tunnel test section, the correction values increase. The verification of lift coefficient corrections in this paper is concentrated, where very good agreements have been obtained comparison with several well-known analytical methods.