Flow structure of low-aspect-ratio rotating wings from dye visualization

Efforts to develop bio-inspired micro air vehicles (MAV) have motivated flapping-wing aerodynamics research. A syringe pump delivers the mixture at a very low flow rate to a hypodermic tube, which is carefully positioned near the model manually, then removed lengthwise. Once ensuring the dye is stationary, the run is executed. Identifying injection locations to highlight specific features is a trial-and-error process; the dye is typically injected in thin, chordwise strips on the aft plate surface where vorticity generation will occur or injected ahead of the plate and entrained. Important in light of numerous recent investigations using volumetric DPIV data, dye visualization can provide truly instantaneous information for comparison in cases where the suitability of reconstructing a volume from multiple realizations must be verified.