Hydrostatic pressure in the Bernoulli Equation

[JJBladester]

Homework Statement

The hydrostatic pressure term in the Bernoulli equation (ρgz) decreases with fluid depth. Why?

Homework Equations

Bernoulli Equation (multiplied by density ρ to give us pressure units):

$$P+\rho\frac{V^2}{2}+\rho gz=constant$$

The Attempt at a Solution

In the hydrostatics chapter in my book, hydrostatic pressure, ρgh, increases with depth. However, in the Bernoulli equation, the hydrostatic pressure term ρgz decreases with depth.

Is this just because we're selecting a coordinate system where the vertical direction faces up instead of down?

What physical significance does this have?

 

[tiny-tim]

Hi JJBladester!

Is this just because we're selecting a coordinate system where the vertical direction faces up instead of down?

Yes, h = -z.

What physical significance does this have?

erm … swim the way the bubbles go?