Intuitively, why does pressure decreases as fluid velocity increases

[loveoforganic]

If anyone could help, I'd like a non-math based explanation - just something logical. Thanks 🙂

---

Members don't see this ad.

 

[G1SG2]

If anyone could help, I'd like a non-math based explanation - just something logical. Thanks 🙂

Think of it as conservation of energy. The increase in fluid velocity/increase in kinetic energy occurs at the expense of losing potential energy (as in losing gravitational potential energy and gaining kinetic energy for an object dropped near the surface of the earth). This is what Bernoulli's equation is really about.

 

[loveoforganic]

Ah ok. So you could look at it as "as the velocity of a fluid increases, the portion of its energy going toward kinetic energy increases, and thus the portion of its energy going toward pressing on the pipe decreases?"

 

[G1SG2]

Ah ok. So you could look at it as "as the velocity of a fluid increases, the portion of its energy going toward kinetic energy increases, and thus the portion of its energy going toward pressing on the pipe decreases?"

I suppose that would be a good way to think about it 👍

 

[loveoforganic]

Thanks for the help!

 

[phEight]

I don't know if this will make sense but I imagine that fluid velocity, lets say in a circular pipe, is fastest at the center (because if fluid molecules touch the walls, the wall will slow those molecules down). Intuitively it makes sense to me to think that as fluid velocity increases, there is basically less time for the fluid to put pressure on the walls, it's too busy speeding through the center of the pipe.

 

[kimbebe51]

Think about a tornado, the reason why the roof comes off from the house is not due to the 1000 mile per hour winds but because of the pressure difference. The tornado is moving at a fast velocity so with that comes a drop in pressure. The interior of the house has a normal pressure relative to the outside of the house in which the pressure has dropped due to the tornado. The roof comes off the house and the windows break because the pressure inside the house is so great compared to the outside.

I know this is a very simplified explanation but I hope this helps.

 

[ThirdEye]

As you increase the velocity, the tendancy of the molecules to go outward decreases (less resistance and less pressure). Decrease the velocity and their tendancy to go outward increases.