タンポポ冠毛の後流

抄録

There are two kinds of seeds that fly by wind, pappose seeds and winged seeds. The former is known to make parachuting flights, which utilize the drag force acting on the pappus. Each flying seed is designed to have a small rate of descent and to float in the air current as long as possible, according to their environmental conditions. The common dandelion is a classic example of a wind-dispersed plant and facilitates flight by the pappus, which is composed of numerous filaments and gaps. The spatial structures in high porosity pappus are presumed to the key to drag enhancement and long-distance dispersal. In the present study, in order to investigate the relationship between the spatial characteristics of pappus with high porosity and flow behavior around the pappus, smoke flow visualization was performed by changing the porosity of the pappus. The drag coefficient decreases with increasing the porosity of the pappus. However, even if the same porosity, the aerodynamic characteristics were changed by the spatial structure of the pappus.