Reconfiguration of plumed-seed inspired poroelastic cluster in fluid flow

Plumed seeds, such as dandelion or milkweed seeds, can fly a distance of kilometers while other types of wind-dispersal seeds disperse a few hundred meters at maximum. The plumed seed consists of many microscopically thin and elastic plumes appended to an achene, and it is well known that this porous structure enables superior flight performance by augmenting counter-gravity drag forces, which is essential for long-distance dispersals. Although the effects of porosity have been of interest recently, it remains unexplored how the elastic deformation of individual plumes and the resulting reconfiguration of the whole seed change aerodynamic loading. In this study, we numerically examine the effect of elasticity on reconfiguration and drag force for a porous cluster of elastic cylinders, by adopting simplified two-dimensional models. In contrast to common plants or elastic fins that streamline and reduce drag forces when subjected to a fluid flow, the poroelastic cluster reconfigures to enlarge the frontal area and therefore increases the total drag force.