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Background-oriented schlieren (BOS) methods suited for large-scale and in-flight testing are presented with special emphasis on the detection and tracing of blade tip vortices in situ. Retroreflective recording and photogrammetric epipolar analysis for the computation of the vortices' spatial coordinates in the wind tunnel are described. Feasibility and fidelity of referencefree BOS in conjunction with natural formation backgrounds and related evaluation methods are discussed, additionally, illustrating their simplicity and robustness. Results of successful image acquisition from a chaser aircraft are presented allowing vortex wakes to be identified at a wide range of flight attitudes, including complex maneuvers.

The Magnus effect on a generic 6.37 diameter long tangential-ogive-cylinder type projectile was studied by means of 3D Reynolds-averaged Navier-Stokes (RANS) simulations and wind tunnel measurements. The nominal Mach number was 3 and the Reynolds number, based on the model length, was 1.09 x 10^. The simulations provided a profound insight into the flow structure and revealed a shift of the cross-flow separation lines as a consequence of the spin. This was shown to be the primary source of the Magnus side force for the higher angles of attack in the investigated range. The nonlinear dependence of the Magnus side force on the angle of attack was analyzed and reached a maximum value between 10 and 15 deg before decreasing again. The occurrence of secondary vortices in this range of angles of attack is presented as an explanation for a locally negative Magnus side force portion acting on the model.