###### K

## Knudsen number

Knudsen number is the ratio of the molecular mean free path length to a representative physical length scale. It is represented as:

Knudsen number is the ratio of the molecular mean free path length to a representative physical length scale. It is represented as:

Keulegan–Carpenter number describes the relative importance of the drag forces over inertia forces for bluff objects in an oscillatory fluid flow. It is also known as period number.

Iribarren number is used to model several effects of surface gravity waves on beaches and coastal structures. It is also known as the surf similarity parameter and breaker parameter. While

The Hagen number is the forced flow equivalent of the Grashof number. It is represented as:

The Grashof number (Gr) is the ratio of the buoyancy to the viscous force acting on a fluid. In mass transfer, temperatures will be replaced with concentration.

In fluid dynamics, the Graetz number (Gz) characterizes laminar flow in a conduit. It is expressed as: In mass transfer, it is the ratio of momentum diffusivity to mass diffusivity.

Görtler number is the ratio of centrifugal effects to the viscous effects in the boundary layer.