Different Types of Energies or Head of a Liquid in Motion. The following are the three types of energies or head of flowing liquids:

1. Potential energy or potential head. It is due to the position above some suitable datum line. It is denoted by z.

2. Kinetic energy or kinetic (or velocity) head. It is due to the velocity of flowing liquid. Its value is given by v2/ 2g, where v is the velocity of flow and g is the acceleration due to gravity.

3. Pressure energy or pressure head. It is due to the pressure of liquid. Its value is given by p/w, where p is the pressure in N / m2 and w is the weight density of the liquid in N / m3.

Note: The total energy or total head of a liquid particle in motion is given as follows :

Total energy, E = Potential energy + Kinetic energy + Pressure energy

and

Total head, H = Potential head + Kinetic head + Pressure head