Transmission of force by fluids.

• The static pressure acts equally in all directions at the same time.
• The static pressure always acts at right angles to any surface in contact with the fluid.

When a pressure is applied to one end of an enclosed volume of fluid the pressure is transmitted equally to every other part of the fluid.

Pressure drop

When a fluid flows through a pipe, frictional forces will mean that energy is expended. This results in the work pushing the fluid into the pipe is greater that the work that could be done by the fluid exiting the pipe, thus resulting in a pressure drop.

The pressure drop (p) per unit length of the pipe is approximately proportional to the square of the mean fluid velocity.

Thus doubling the volume rate flow quadruples the pressure drop per unit length of pipe.

In the barrage the oil is transported from the oil tank and through the pipes via a hydraulic pump when needed to open the sluice gates so the pressure drop must be taken into account.