Fluids

Step 1: Definition.
The coefficient of viscosity describes the internal friction in a fluid as it resists the motion of its layers. A higher viscosity indicates a thicker fluid that resists motion more, while a lower viscosity indicates a thinner, more fluid substance.
Step 2: Formula.
The formula for the coefficient of viscosity is given by: This relationship shows that viscosity depends on the applied force, the area through which the fluid flows, and the velocity gradient.
Step 3: S.I. Units.
The S.I. unit of viscosity is the pascal-second (Pa·s), which can also be written as . This unit represents the force per unit area needed to produce a certain velocity gradient in the fluid.