Fig. 9. Peak vorticity of LEV core and difference in peak vorticity between
single-wing and two-wing flapping conditions. Peak vorticity was measured
within the investigation areas shown in
Fig. 7. (A) Difference
(ab) in peak vorticity between the one- (b) and two-wing (a) flapping
conditions at five different DPIV layers, as indicated by the pictograms. (B)
Averaged values of all five DPIV layers. Absolute LEV peak vorticity while
flapping one wing is plotted in red; peak vorticity while flapping two wings
is shown in blue. Vorticity difference (ab) in B is shown in green.