Hydraulic Principles

Question 1

What do all fluids have including air?

Answer 1

Static pressure

Question 2

How do they get static pressure?

Answer 2

With no other external force applied, static pressure results from the energy of the fluid (temperature) and the force of its own weight

Question 3

Two containers filled with water example

Answer 3

The static pressure at the bottom of the containers is exactly the same because the height of the water above it is exactly the same
The force which causes the static pressure is the weight of the water itself

Question 4

Incompressible fluid law

Answer 4

Pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio (initial difference) remains the same

Question 5

Fluids compressibility

Answer 5

Air is very compressible

Other fluids such as oil and water are almost completely incompressible

Question 6

E.g. 500 lb load on an enclosed column of air and an enclosed column of oil

Answer 6

The force would be instantaneously transmitted through the oil but not through the air-which would, at first, compress

External force to the fluid rather than force of its own weight

Question 7

What does this external pressure represent?

Answer 7

Potential energy which can be put to work in the form of kinetic energy, provided we develop the system that allows movement

Question 8

Hydraulic power

Answer 8

The rate of doing work