タンポポ冠毛の隙間構造が空力特性に及ぼす影響

抄録

Dandelions are highly successful perennial herbs that can be found in temperate zones all over the world. The common dandelion uses a bundle of drag-enhancing bristles (the pappus) that helps to keep their seeds aloft. Unlike a solid body, a dandelion pappus is filamentous, so air can flow through it in addition to going around it. During a seed’s flight, aerodynamic interactions between filaments enhance the drag on the pappus and it is pointed out that the pappus generates four times as much drag as a solid membrane of the same surface area. The pappus creates a parachute flow configuration and this passive flight mechanism is highly effective, enabling seed dispersal over formidable distances. However, the physics underpinning pappus mediated flight remains unresolved. In the present study, the float testing is performed by using the several types of a real dandelion pappus in a vertical air flow pipe. It is confirmed that the generating drag of the pappus is affected by the surface geometry of the filaments.