Increase Velocity of Fluid: Less Pressure?

[bluejay27]

Why is there less pressure if the velocity of the fluid is increased?

 

[bluejay27]

I obtained the answer! It deals with the continuity equation, where the mass of a moving fluid does not change as it flows. Thus, the volume flow rate has to be equal at all times.

 

[bluejay27]

Nevermind that still does not answer my question. Why is there less pressure when the velocity of fluid is increased?

 

[bluejay27]

Nevermind that still does not answer my question. Why is there less pressure when the velocity of fluid is increased?

You can look at the Bernoulli equation! Since, the left side of its equation is constant, the right side must equal to each other. If there is a smaller cross-section, there will be a higher speed and in order to make the equation equivalent to the left side of the equation, the P at the right side of the equation must decrease.

 

[russ_watters]

I obtained the answer! It deals with the continuity equation, where the mass of a moving fluid does not change as it flows. Thus, the volume flow rate has to be equal at all times.

That's one of two parts: that's conservation of mass (flow). The other is conservation of energy.

 

[zanick]

ive often wondered what causes the molecules to accelerate. some say that the neck down is a kind of "velocity filter" and allows the high speed vibrations of the molecules to prioritize the ones pointed in the right direction, through.

 

[Austin Z W]

Been a while since I took physics, but I believe that because the left side of the Bernoulli equation stays constant the pressure must vary proportionally with the velocity. So as the water speeds up, it must exert a lower pressure on its surroundings.