The passage of a shock front and the associated drift flow over a two-dimensional airfoil, at an angle of attack mounted in a shock tube, generated a columnar spiral starting vortex that interacted with the normal reflected shock. Interferometric investigations of this interaction extended considerably earlier schlieren observations by Hollingsworth and Richards. The generation of a progressive cylindrical acoustic wave front centered on the transmitted vortex and its alternate compression-rarefaction nature, as predicted by linearized analyses by Hollingsworth and Richards and later by Ribner, was experimentally verified and deviations from the predicted pressure amplitude distribution were discovered. A semiempirical relation for the wave-front pressure-amplitude distribution (expressed as a linear combination of quadrupole, dipole, and monopole acoustic sources) was found to represent closely the experimental results. The time variation of the core density of the transmitted vortex was deduced. The spiral vortex decayed essentially as a circular, incompressible viscous vortex until a neighboring high-density region appeared and the vortex decayed at a faster rate. The interaction of the reflected shock with the vortex street generated behind a circular cylinder, resulted in an abrupt change in vortex spacing and rapid dissolution of the vortex street. No well-defined acoustic wave fronts were evident behind the reflected shock front.