The mechanisms of leading-edge vortex (LEV) formation and its stable attachment to revolving wings depend highly on Reynolds number (
$\textit {Re}$
). In this study, using numerical methods, we examined the
$\textit {Re}$
dependence of LEV formation dynamics and stability on revolving wings with
$\textit {Re}$
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
$\textit {Re}$
decreases from 1000 to 10. Moreover, the primary mechanisms contributing to LEV stability can vary at different
$\textit {Re}$
levels. At
$\textit {Re} <200$
, the LEV stability is mainly driven by viscous diffusion. At
$200<\textit {Re} <1000$
, the LEV is maintained by two distinct vortex-tilting-based mechanisms, i.e. the planetary vorticity tilting and the radial–tangential vorticity balance. At
$\textit {Re}>1000$
, 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
$\textit {Re}$
. In addition, the contribution of planetary vorticity tilting in LEV stability is
$\textit {Re}$
-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-
$\textit {Re}$
revolving wings.
Video: Leading edge vortex formation in aquatic swimming
