Effect of Dandelion Pappus Morphology on the Vortex Generation

Plants like the common dandelion (Taraxacum Officinale) and the common salsify (Tragopogon Porrifolius) rely on their parachute-like pappuses (hair) to enable wind-dispersion. The radially spreading pappuses naturally creates radially varying porosity; Indeed, near the center the inter-pappus distance would be smaller than the boundary layer formed over individual hairs during descent, effectively behaving like a solid disk within a small radius. In turn, the vortex forming on the falling seed is expected to depend on the pappus filament number and length. In this presentation, we will show the study elucidating the effect of pappus morphology on the vortex ring size (width and length). This work looks to expand the existing body of knowledge by considering how pappus geometries are optimized to create vortex rings needed to carry seeds of a given mass.