Investigation of flow structure through Asteraceae seed head

Dandelion (Taraxacum officinale) and salsify (Tragopogon dubius) are two species in the Asteraceae plant family that produce seed heads composed of wind dispersed seeds. For these seeds to be dispersed, they must first be released, or abscised, from the seed head. Previous studies have looked at the effects of wind speed, wind direction, temperature, turbulence, and humidity on seed abscission. Other studies have explored the flow structure through the pappus of dandelion seeds post-abscission. In this study, we explored the flow structure through the seed head pre-abscission using the smoke-wire visualization technique. Our results show that these seed heads act as rough, semi-porous, deformable spheres. We then compared these flow structures to that of flows around model spheres to investigate the effects of porosity and roughness.