Effects of Reynolds number on leading-edge vortex formation dynamics and stability in revolving wings

The mechanisms of leading-edge vortex (LEV) formation and its stable attachment to revolving wings depend highly on Reynolds number . In this study, using numerical methods, we examined the dependence of LEV formation dynamics and stability on revolving wings with ranging from 10 to 5000. Our results show that the duration of the LEV formation period and its steady-state intensity both reduce significantly as decreases from 1000 to 10. Moreover, the primary mechanisms contributing to LEV stability can vary at different levels. At <[CDATA[Re}, the LEV stability is mainly driven by viscous diffusion. At <[CDATA[200, the radial-tangential vorticity balance becomes the primary contributor to LEV stability, in addition to secondary contributions from tip-ward vorticity convection, vortex compression and planetary vorticity tilting. It is further shown that the regions of tip-ward vorticity convection and tip-ward pressure gradient almost overlap at high, the LEV is maintained by two distinct vortex-tilting-based mechanisms, i.e. the planetary vorticity tilting and the radial-tangential vorticity balance. At 1000$]. In addition, the contribution of planetary vorticity tilting in LEV stability is -independent. This work provides novel insights into the various mechanisms, in particular those of vortex tilting, in driving the LEV formation and stability on low- revolving wings.