Real case (friction & height changes considered)

Friction considered / height changes neglected

Friction neglected / height changes considered

Ideal case (friction & height changes neglected)

$$ p_{rel}= p_{hydro}= \rho \cdot g \cdot \Delta h = \rho \cdot g \cdot ( h - h_{ref}) $$

$$ \it{v= \frac{\dot{\mathbf{V}}}{A} }$$