Fluid Flow Classifications: Understanding Laminar, Turbulent, Compressible and More

Steady and unsteady flow

In a steady flow, the fluid characteristics such as density, velocity, pressure, temperature, etc. at a point do not change with time.

For steady flow, steady_flow_equation

> In a steady flow, the shape of the stream tube remains unaltered.
If fluid characteristics change with time, then the flow is said to be unsteady.

Uniform and non-uniform flow

Uniform flow defined as the type of flow in which velocity vector at all points in the flow is same at any given instant of time.
For uniform flow, uniform_flow_equation

If the velocity of flow at any instant of time changes with repeat to space, the flow will be non-uniform.
For nonuniform flow, nonuniform_flow_equation

Compressible and incompressible flow

Compressible flow is defined as the type of flow in which the density of the fluid changes significantly. If the fluid density remains same from point to point, the flow is called incompressible. Liquids are generally considered as incompressible and gases are compressible.

Laminar and turbulent flow

In laminar flow, the fluid particles move in layer sliding smoothly over adjacent layer, and streamlines are straight and parallel. It is also called viscous flow or streamline flow.
If fluid particles have random, erratic movement, then it is called turbulent flow. It leads to intermixing of the various layers of fluid.

Rotational and irrotational flow

If fluid particles rotate about their own axis while flowing along the stream, then the flow is called rotational. If the fluid particle does not rotate about their own axis, then the flow is irrotational.

Read: Free And Forced Vortex Flow