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Why Laminar Flow is AWESOME - Smarter Every Day 208
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CEFR 等级
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Hey, it's me Destin, welcome back to Smarter Every Day.
I love,
laminar flow.
And people send me tweets about laminar flow,
all over the internet, its time to do,
the laminar flow video.
Check this out, big pool.
We're going to see if we can make, laminar flow happen.
I should be able to poke a hole, in this pool,
and get a glassy looking jet,
that comes out this pool. That's what laminar flow is.
It's very orderly, looks like glass.
Okay, so here we go, ready,
three, two, this feels so wrong.
Let's see if we get laminar flow,
no, we don't.
(laughs)
Now I've got a hole in a pool.
Okay, laminar flow is a function of geometry,
obviously I had the wrong geometry.
We're going to try a big spike, here we go.
Oh golly.
Okay. (Laughs)
Alright.
No, it doesn't work.
So my shape's not right.
My shape's not right, what do I do.
Work, work, work, work with me.
Ah, there we go, okay, so.
I got laminar flow right here,
and its going turbulent, right here.
Why?
Laminar flow is a function of the geometry, the velocity,
and the kinematic viscosity,
of the fluid that you're working with.
Right now, my velocity, is not fast enough,
to have laminar flow, because there's not enough pressure,
so if I move it down, I should have more pressure.
So, let's plug this back up,
well now I have a problem.
That's out.
I'm doing a bad job of explaining laminar flow,
what we need to do, we need to go, around the world,
to different places I've observed laminar flow
in the past several years.
And we need to let me show you, various things
that I've seen along the way.
Laminar flow is orderly, all streamlines are parallel,
and there's no mixing of the flow.
It's all like how you would imagine,
water flowing through pipe,
everything is straight and parallel.
Turbulent flow however, is chaotic,
there's pressure fluctuations throughout,
you get the idea.
Engineers have this special term,
called the Reynolds Number.
To try and help predict, what type of flow,
they might be dealing with.
The top of the equation are the things
that describe the flow itself,
like the velocity, the density, the geometry, etc.
But the bottom of the equation is viscosity of the fluid.
Like how thick the fluid is, like water vs honey.
A lower Reynolds Number,
means that the flow is more laminar,
and in my opinion, more awesome.
But a high Reynolds Number means that it's more turbulent.
So if you look at the equation,
you can kinda see what's going on here.
If you have more viscosity,
that means Reynolds Number gets smaller,
therefore the flow is more laminar.
But if you increase the velocity of the flow,
or the size of the flow,
Reynolds Number gets bigger,
therefore you have more turbulent flow.
If you keep Reynolds Number and the mock number the same,
you can make a model of whatever you're trying to fly,
and you can get a good idea if turbulence or laminar flow
is going to happen over the model.
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