Figure 4.
(a) Strength of the different vortices measured as the percentage of the required weight support calculated using downstroke stop vortex, upstroke start vortex and LEVD (secondary vorticity tentatively identified as leading-edge vortex, see text for details) as measured in the parasagittal plane, and wingtip vortex at downstroke and wingtip vorticity during the upstroke, as measured in the transversal plane. (b) Normalized circulation (Γ/Uc) for the wingtip and wing root vortices of the two stroke phases, where U is the average wingtip velocity. Values are means ± s.e. (n = 4).