Why Does Increasing Velocity Decrease Pressure in Fluid Dynamics?

[Wombat11]

Homework Statement

This Is more of a conceptual question. If the equation for dynamic pressure is 1/2(density)(velocity)^2 then as velocity increases the pressure would also, but I was told that as velocity increases pressure decreases. If anyone could explain this to me that would be great.

 

[gneill]

As an isolated term, your description of the relationship between dynamic pressure and velocity would be correct. But you will find that as applied to fluid flow there are conservation laws that tie it to other quantities.

Take a look at the Bernoulli equation.

 

[Wombat11]

In Bernoulli's equation is it pretty much saying that (static/gauge pressure)+ (pressure due to change in height)+(dynamic pressure) is a constant? Also my teacher manipulated the equation so it was Gauge pressure=(d)(g)(change in height)+ 1/2(d)(change in velocity)^2. Would it be Gauge pressure or change in Gauge pressure? Thanks.

 

[gneill]

In Bernoulli's equation is it pretty much saying that (static/gauge pressure)+ (pressure due to change in height)+(dynamic pressure) is a constant?

Along a streamline, yes.

Also my teacher manipulated the equation so it was Gauge pressure=(d)(g)(change in height)+ 1/2(d)(change in velocity)^2. Would it be Gauge pressure or change in Gauge pressure? Thanks.

I would think it would be change in gauge pressure, since the other terms are changes.