The fish looks like it is alive and swimming, but is in fact moving due to passive propulsion. The vortices in the water move the fish’s body to cause the tail and head to point different directions. If positioned correctly, as in this GIF, there is a resonance between the vortices and the fish that generates thrust. This means the fish can hold its position or even move up stream without expending any energy.
BEAL, D., HOVER, F., TRIANTAFYLLOU, M., LIAO, J., & LAUDER, G. (2006). Passive propulsion in vortex wakes. Journal of Fluid Mechanics, 549, 385-402. doi:10.1017/S0022112005007925
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Third Prize
This photo says so much about nature and the species that inhabit these spaces. The flow can be seen especially in the fishes dynamic motion.
Third Prize! I like how without understanding any of the math behind the fluid dynamics, other species can learn about different fluid phenomenon and use them to make their life easier.
Third prize
I like the use of black and white in this video because it limits distraction and draws attention to the fish swimming in water.
Second prize
I like how simple this video is – you aren’t distracted by flashy colors, and simply are able to see how the fish interacts with the water.