Fluid dynamics have been around oh, since fluids. Which is to say essentially forever. Many flowers tend to have a generic cone shape, evolved over the ages for one reason, to take advantage that rain happens to obey the laws of fluid dynamics. Ideally, the raindrop can land in a spot just right for the seed, landing off-center, following downward along the bottom, and whipping back out. Its exit at the other end carries an encapsulated seed, hurling it a distance of a meter or more.
Using cameras able to film in the ultra-slow-motion we've all come to love, this study has produced something truly beautiful.
Music is by me.
Credit for this study goes to:
Guillermo J. Amador1 , Yasukuni Yamada1 , David L. Hu1,2
Schools of Mechanical Engineering1 and Biology2
Georgia Institute of Technology, Atlanta, GA 30332, USA
Another very very strange thing I noticed is that their paper, which can be downloaded here on ArXiv contains nothing more than the abstract. I'm sure more analysis is coming.
Here's the abstract:
"Several species of plants have raindrop-sized flowers that catch raindrops opportunistically in order to spread their 0.3-mm seeds distances of over 1 m. In the following fluid dynamics video, we show examples of these plants and some of the high speed videography used to visualize the splash dynamics responsible for raindrop-driven seed dispersal. Experiments were conducted on shape mimics of the plants' fruit bodies, fabricated using a 3D printer. Particular attention was paid to optimizing flower geometries and drop impact parameters to propel seeds the farthest distance. We find off-center impacts are the most effective for dispersing seeds. Such impacts amplify the raindrop's speed, encapsulate seeds within drops, and direct the seed trajectory at angles optimal for long-distance dispersal. "
Another interesting facet to this experiment is their usage of 3d printed flowers. Personally, it's the first I've seen this new technology in a legitimate scientific study.
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Guillermo Amador, Yasukuni Yamada, & David Hu (2011). How flowers catch raindrops ArXiv arXiv: 1110.3993v1