Visualization and Transport Analysis of Non-slender Delta Wing Vortices*

The flow physics of non-slender delta wings are complex and relatively poorly understood in comparison with their slender counterparts.  A vorticity transport analysis on a low-Reynolds number (O(10⁴)), sharp-edged delta wing, with sweep angle of 50 degrees, showed that the vorticity in the leading-edge vortices was generated primarily near the apex, with convective and diffusive vorticity transport processes governing LEV evolution along the leading edges [Buchholz, Wabick, Manazir, and Snider, APS DFD 2019].  In the present work, we examine a similar delta wing geometry in a wind tunnel at Re = O(10⁵) using volumetric particle tracking velocimetry.  A vorticity transport framework is used to characterize leading-edge vortex evolution under these conditions.  Whereas the vorticity transport budget, which quantifies various physical mechanisms governing LEV strength, is in essence a reduced order model of the flow, we also investigate these transport mechanisms in the context of flow field modal decomposition.  Reynolds number effects are also considered.