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Bernoulli's Theorem
How pressure and velocity interact
static pressure + dynamic pressure = total pressure = constant
static pressure + 1/2 x density x velocity2 = total pressure = constant
General Concept:
The Bernoulli effect is simply a result of the conservation of energy. The work done on a fluid (a fluid is a liquid or a gas), the pressure times the volume, is equal to the change in kinetic energy of the fluid.
General Facts:
Where there is slow flow in a fluid, you will find increased pressure.
Where there is increased flow in a fluid, you will find decreased pressure.
In a real flow, friction plays a large role - a lot of times you must have a large
pressure drop (decrease in pressure) just to overcome friction. This is the case
in your house. Most water pipes have small diameters (large friction), hence the
need for "water pressure" - it is the energy from that pressure drop that goes to friction.
Example: the showerhead
A showerhead (if you have a fancy one) has a number of different operation modes.
If you go for the "massage" mode, you are moving a little water fast.
For the "lite shower," you are moving a lot of water slowly.
It takes the same amount of energy to move a little water fast as it does to move a lot of water slowly.
This is the amount of energy you have due to your "water pressure."
