Cross-Stream PIV Characterization of the Prandtl-D3C Wake

This paper presents the cross-stream particle image velocimetry (PIV) measurements of the wake structure behind a Prandtl-D3C wing configuration tested in the University of Dayton Low-Speed Wind Tunnel. Previous computational and experimental efforts have suggested that bell-shaped lift distributions may suppress or delay tip vortex roll-up. However, direct experimental validation using cross-plane PIV has been lacking. In this study, PIV data were acquired at three downstream planes (2c, 3c, and 4c) under varying angles of attack and compared against FlightStream® panel method simulations. Results show a distinct inboard vorticity structure with no evidence of conventional wingtip vortex near the design condition, providing strong support for the hypothesized wake behavior. Background subtraction and multi-plane stitching were employed to resolve weak cross-stream velocity components. These findings contribute new experimental insight into the wake dynamics of non-elliptically loaded wings and support ongoing interest in low-vorticity, high-efficiency lifting surface designs.