Deconvolution Correction for Wandering in Wingtip Vortex Flowfield Data

Abstract

A deconvolution method is presented for correcting the smoothing effect caused by vortex wandering in velocity measurements of wingtip vortices. Flowfield velocity data are acquired using SPIV in an open-jet wind tunnel at several streamwise locations. A parametric Wiener filter that incorporates an estimate of the noise-to-signal ratio and the joint probability density function of the vortex motion is applied to correct for the wandering using a Fourier-domain deconvolution approach. In order to assess the accuracy of the correction, the instantaneous vector fields obtained from SPIV are shifted to the mean vortex center, and then averaged to yield the uncorrupted vortex flowfield. The unshifted mean flowfield data is then corrected by deconvolution and is then compared with the uncorrupted vortex flowfield. The results show that the deconvolution technique accurately corrects for the vortex wandering.