Kinematic viscosity is defined to be the resistance of a fluid concerning flow and deformation under gravity. It simply tells how easy it is for a fluid to move through a medium, measured as the ratio of dynamic viscosity to fluid density.

Units: Kinematic viscosity is quoted in square metres per second (m²/s) but can also be expressed in stokes (1 stokes = 10⁻² m²/s).

Significance: How such liquids behave under various conditions is important when considering applications involving engineering, meteorology, and biology, such as fluid transport in pipes, aerodynamic resistance, and circulatory flow.

Essentially, kinematic viscosity describes how the fluid moves and responds to force; thus, it is one of the most important fluid dynamics properties.

Formula 

The formula for the kinematic viscosity is as follows,

ν = μ/ρ

Where 

• μ = absolute or dynamic viscosity,

• ρ = density

Solved Problem

Problem: A fluid has absolute viscosity of 0.98 Ns/m2 and kinematic viscosity of 3 m2/s. Find the density of fluid?

Solution: 

Given,

Absolute viscosity μ = 0.98 Ns/m2

kinematic viscosity ν = 3 m2/s

The formula is given as,

ν = μ/ρ

The density is given by,

ρ = ν/μ

ρ = 3/(0.98)

ρ = 3.0612 kg/m3

Therefore, the density of a fluid is 3.0612 kg/m3.