Fig. 6. The late downstroke leading-edge vortex (LEV) of Manduca sexta.
Flow fields resolved after subtraction of the freestream velocity (3.5 m
s-1). (A,B) Vorticity and streamlines in the wake and near-wing
flow field of Manduca, shown to provide context. (A) The vortex sheet
is shed from the trailing edge of the wings; (B) how the streamlines spiral
into a stable focus at a midwing location, just above the leading edge. (C)
Two excerpts from the corresponding force trace, with the output normalised
relative to body weight. The instant the three images were taken is shown by a
broken line at the peak in relative upforce (2.2 times that required to
support body weight).