Turbulent Flow is MORE Awesome Than Laminar Flow

Turbulent Flow is MORE Awesome Than Laminar Flow

Everyone loves laminar flow but turbulent flow is the real MVP.
A portion of this video was sponsored by Cottonelle. Purchase Cottonelle Flushable Wipes and try them for yourself: https://bit.ly/2WJm9Hq

Special thanks to:
Prof. Beverley McKeon and team https://www.mckeon.caltech.edu
Destin from Smarter Every Day https://www.youtube.com/smartereveryday

I got into turbulent flow via chaos. The transition to turbulence sometimes involves a period doubling. Turbulence itself is chaotic motion, it is unpredictable and sensitively dependent on initial conditions. What surprised me is all the ways turbulent flow is useful to us. It is diffusive, meaning it causes mixing. This is useful in jet engines or rocket nozzles (which Destin studies) and is important to achieve in microfluidic devices, which are so small that turbulent flow is actually difficult to achieve. Turbulent flow can energize a boundary layer, which is important to maintain flow attachment over a wing, maintaining lift and delaying stall. Similarly a turbulent boundary layer over a golf ball reduces pressure drag allowing golf balls to fly further. This is the reason for the dimples on golf balls. Flow transitioning to turbulence in the wake of a bluff body can create periodic vortex shedding. This beautiful phenomenon can be seen in the von Kàrmàn vortex street in clouds viewed from space. Turbulence is everywhere, in the air currents in a room, in your aorta, in the breaths you exhale, in oil pipelines and water pipes, in the flow over cars and ships and planes. Animals have evolved for it (like dead fish swimming up stream) and we have engineered our environment, our planes and golf balls for it. Laminar flow may be nice to look at (which is why we use it in decorative fountains) but turbulent flow does the real lifting.

Animations by:
Jonny Hyman (Sun, Jupiter, Reynolds, airfoil, Earth time-lapse)

Research and writing:
AJ Fillo and Derek Muller. AJ also created the wind tunnel golf ball shots

Filmed by:
Daniel Bydlowski and Derek Muller

Additional footage:
Images of Jupiter courtesy of NASA
Turbulence in air currents by the Physics Girl, Dan Walsh, and Grant Sanderson https://youtu.be/N7d_RWyOv20

illBird “Shaffuru” https://youtu.be/5rkt53fNMgc
From EpidemicSound https://epidemicsound.com “Seaweed” “Colorful Animation 4”
Kevin MacLeod https://incompetech.com “Sneaky Adventure”

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57 Responses

  1. TheDragonaf1 says:

    As a master’s in mathematics the Navier Stoke equations brings back nothing but very difficult memories.
    Edit: this video is basically the summery of my fluid dynamics course.

  2. XepptizZ says:

    “Turbulence literally makes it rain”

    Mic drop

  3. Nostson says:

    “Transitional Flow is the BEST” Video when?

  4. guilhermek32 says:

    Destin: Laminar flow😍
    Entropy: wait a bit!

  5. Seminaia says:

    Derek: “Turbulent Flow is More awesome than laminar flow”
    Destin: “Thems fighting words”

  6. Gil Amesh says:

    Thank you so much Derek for this video. Having one of the most difficult to grasp and explain topics in such a succinct video brings a real smile. As someone who has publications in high Reynolds number turbulent pipe flows, turbulent boundary layers as well as engineering surfaces for desired roughness and it’s applications to drag reduction on spheres, this is one of my favourite videos of all time. Having Professor McKeon there as well is great, she is a true outstanding leader in the field. Please don’t stop making videos 🙂

  7. BiggityBoggityBoo says:

    What about that wipe Vs standard toilet tissue though. That’s what I wanted to see. Paper towel should be put into a bin not the toilet.

  8. A penguin named Sharon says:

    Destin from SmarterEveryday after seeing the title: *Actually No*

  9. IN A FLASH says:

    I knew destin was gonna be in this, he just can’t resist laminar flow.

  10. Jerrin Chu says:

    *Destin from SmarterEveryDay wants to know your location*
    Edit: *Shows Destin as I type this* There goes my joke

  11. momoProjects says:

    As a Civil Engineer I’m enraged that you are supporting “flushable” wipes. While they are better than baby wipes or paper towels, how about we compare them to toilet paper which the sanitary system is actually designed to handle. As you said, flushable wipes account for 2% of the clogging of the system which is millions of dollars spent to declog the system each year. This is so irresponsible to advocate for people to put flushable wipes in the toilet because they are not actually flushable especially in most parts if the country where the sanitary sewer system is not as strong as New York’s. I’m very disappointed in this partnership and hoped that you would be less willing to sell out the infrastructure of the nation for a quick buck.

    • NateDawg says:

      @Anne Maveera oh my God. That is disgusting. No. You throw it in the toilet. Not in a bin. You would have to empty that bin every time you took a dump. Or get a diaper genie for your bathroom.

    • Kevin Skusek says:

      @NateDawg No, he showed paper towels and not toilet paper at the end as one of the tests.

    • moxy says:

      @NateDawg you’re disgusting and waste air

    • James Love says:

      @NateDawg There wasn’t any toilet paper in the experiment… The comment you’ve replied to mentioned that in the first few sentences.

    • Luke Busellato says:

      @NateDawg some countries don’t really have a functioning sewage system. What you flush down the loo ends up in the river or ocean. So to reduce pollution you put used paper in a bin.

  12. Just A Dude says:

    “When I meet God, I am going to ask him two questions: Why relativity? And why turbulence? I really believe he will have an answer for the first.”
    -Werner Heisenberg, 1976

    • Earijee says:

      Sweet summer child

    • Its_Elkku says:

      @Crazy Average Asian Bitch I don’t believe in God but I do believe that believing any evidence can prove or disprove God’s existence is foolish.

    • Pooass Cat says:

      Check out the philosophical razor of “Newton’s flaming laser sword”. You simply cannot use empirical evidence and science to justify what is irrational and not based in science in the first place. Science and logic shouldn’t mess with religion and religion shouldn’t dabble with science.

      Religion is not “wrong” by any means, it’s just not scientific and thats not a bad thing. Sometimes it’s okay to believe in a greater universal truth and not confine your beliefs to just what you perceive.

    • Diego Bolanos says:

      Simphaty, Empathy, I’m right, You are wrong, My religion,.Your religion, My believe system,.Your believe system. Awareness or lack of it.

      All those thoughts and feelings are what make us, humans, get to the point we are right now, a divided “smart” animal specie that do not agree with each other.

      If you understood the essence of Werner Heisenberg’s quote and still decided to make a point on God, then you are no different than other humans that wanted separation on all of us.

      The whole quote just expresses the statement of Werner about the very high and deep “respect” he had on those scientific subjects.

      You need to understand that an atheist scientists could come up with a similar quote with the simple objective on praying tribute to the complexity of the same subjects.

      And when you are OK with both versions, then my friend you had reach a better state of awareness

    • Aston says:

      @Crazy Average Asian Bitch I always find it funny when someone who likes science says God doesn’t exist. This goes against your own philosophy. How can you say God doesn’t exist? You have no way to prove this

  13. Delta927 Canadien-français says:

    I’m pretty sure this is the closest thing to a disstrack we’ll see from these guys

  14. Mahery says:

    “It’s most notable use is in fountains”
    Particle processing: bruh

  15. Xyril Dan Manuel says:

    you can’t really conclude a wipe “immediately” breaks down after flushing by soaking it for 30 mins in water.

  16. Sushim Shah says:

    16:26-or simply use a bidet like almost every other continent & save life

    • Dirk Djently says:

      I was really looking forward to finding out how this was going to tie into the video topic :/

  17. starship42 says:

    As an aerospace engineer I’m so glad this video was made. I love Destin’s video on laminar flow but I kept thinking “but but but the flow is so much easier to separate if the flow is laminar”
    But also, you can’t just mention that a dead fish can swim upstream in a sentence and move on! That deserves it’s own video! How does something move upstream without it expending energy! How does an object move forwards when you blow on it! The only explanation I have is there is lower pressure closer to where the vortex is shed than far downstream, so the fish is being “blown” upstream by the pressure difference…

  18. Dz73zxxx says:

    Me, an oceanography student, read this title
    “Awesome? Yes.”
    “The derivation? Nope, not at all”

  19. Subscribe to me and I will subscribe back says:

    Just found out that my physics teacher is actually friends with varitasium! We might get on a zoom room wit dis guy!

  20. Kastro44 says:

    “Turbulent flow is MORE awesome than laminar flow”
    Destin: “-Impossible…”

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