2018 was a busy year for me with over 40 days of business travel, 10 invited talks, and a whole slew of new YouTube videos on top of regular FYFD posts. But now it’s time for the traditional look back at the top 10 FYFD posts of 2018, according to you:
1. Swimming so easy a dead fish can do it
2. The wall of lava lamps that helps secure the Internet
3. Jellyfish versus vortex ring
4. Crushing crayons in a hydraulic press shows off the sharkskin instability
5. Vortex ring from an exploding meteor
6. Starburst patterns form when avalanching materials size separate
7. Kelp change shape depending on their currents
8. The creepy hydraulics of a spider’s gait
9. Pneumatically-driven, 3D-printed plants of the future
10. Exothermic chemistry visualized in infraredThis year’s list is an interesting mix – some biology, vortex rings, non-Newtonian and granular physics; it’s a good list for some of the more unexpected sides of fluid dynamics.
If you’d like to see more great posts like these, please remember that FYFD is primarily supported by readers like you. You can help support the site by becoming a patron, making a one-time donation, or buying some merch. Happy New Year!
(Image credits: fish - D. Beal et al.; lava lamps - T. Scott; vortex ring - V. de Valles; crayons - Hydraulic Press Channel; meteor - P. Horálek; rotating drum - I. Zuriguel et al.; kelp - J. Hildering; spider - R. Miller; hydrophytes - N. Hone; chemistry - Beauty of Science)
Many species of kelp change their blade shape depending on the current they experience. In fast-moving waters, the kelp grows flat blades, but when the water around them is slower, the same plant will grow ruffled edges on its blades. In a slow current, the ruffled version’s extra drag causes it to flutter up and down with a large amplitude. That helps spread the blades out to catch more sunlight and increase photosynthesis, but it comes at the cost of higher drag, which could tear the plant from its holdfast.
In contrast, the flat-bladed kelp collapses into a more hydrodynamic shape. This clumps the flat blades together, making photosynthesis harder, but it streamlines the kelp, making it easier to resist getting ripped out by fast-moving tides. (Image credit: J. Hildering; research credit: M. Koehl et al.; submission by Marc A.)
Turbulence, the chaotic regime of fluid dynamics, is a complicated beast. It’s hard to analyze or predict, but we do understand some general ideas about it, like the fact that energy starts out in large eddies, cascades down smaller and smaller ones, and finally gets dissipated at the smallest scales, where viscosity snuffs them out. But that’s only true in three dimensions.
Two-dimensional turbulence – what you get when you confine your fluid to a flat plane – is even weirder. When turbulence is flat, you can actually get an inverse energy cascade, where the energy of small eddies can add up to feed bigger ones. For awhile, this was treated as a mathematical curiosity; after all, we live in a three-dimensional world. But there are situations in life that are nearly two-dimensional, like the surface of a soap bubble or the atmosphere of a planet (which is typically exceptionally thin compared to the planet’s radius). And, little by little, scientists are collecting evidence that this inverse cascade – a flow of energy from small scales to larger ones – does actually happen in the real world. Understanding how this works may explain why hurricanes can intensify even when conditions are “wrong” and how Jupiter’s Great Red Spot has persisted for centuries. To learn more, check out Quanta Magazine’s full article on the work. (Image credit: NASA et al., M. Appel; via Quanta; submitted by Kam-Yung Soh)
Have reckless self confidence.
Wear the shirt. Talk to the girl. Write your story. Try that new hobby. Visit a new place. Order that one dish you always wanted to but haven’t.
Know that you were put on this earth for a limited time and you were not suppose to live in fear of others or yourself.
16.04.
Rewriting my Histology notes and already hanging behind in the second week of the semester 👍 But coffee, plants and the blue sky keep my heart happy 🌱
The last couple days have been filled with pages of notes and preparations for the coming week. There never seems to be enough hours in the day, never mind spare time to do all the reading I’d like, and I’m looking forward having a few hours to catch up this weekend.
monday, 21 · august 2017
hi guys!!! seems like a I haven’t posted in years!! today I decided to share with you my most recent purchases! i had been wanting a record player for years, found this one on sale so decided to spend my birthday savings on it! also got five records but they haven’t arrived yet! I also decided to go big this time and got the LEUCHTTURM1917 but this time it’s the A4 size! I’m gonna be looking for inspo to see how I’m gonna do my bullet journal this time and will share it with all of you. Hope you are all having a wonderful time, whether you are still on summer break or you started school already! ✨
Daniel S. Silver, The Last Poem of James Clerk Maxwell, «Notices» of the American Mathematical Society, Volume 55, Issue 10, November 2008, pp. 1266-1270 (pdf here)
Monday | April 16, 2018
April Study Challenge #16: One good piece of advice? View your homework assignments as opportunities to learn instead of tasks to get done. I find that doing so makes me more focused on my work.
I don’t know why but I have such positive vibes this week! Midterms are coming up but for some reason I’m so excited for the rest of this quarter. I’m really eager to learn more about physics, math, and everything in general.
Quote of the Day: “Failure is just practice for success.” - Unknown
