The technical processes in hydraulics are essentially based on the following basic laws of physics:
Pascal's law:
(Blaise Pascal, 1623—1662). Every force acting on a stationary fluid generates a pressure that propagates in all directions with the same magnitude.
This the basic law of hydrostatics. All force and pressure processes in fluids are based on this law. As the hydraulic fluid must be transported from the place it is generated (pump) to the place the energy is given up (motor, cylinder), other laws of hydrokinetics need to be taken into account:
Continuity law (conservation of mass):
This law states that a flow rate always remains the same even if it flows through cross-sections of different size. This means that as the cross-section become smaller, the velocity must be higher: