Types of Fluid Flow:

•       Steady and unsteady flow.
•       Uniform and non-uniform flow.
•       Laminar and turbulent flow.
•       Compressible and incompressible flow.
•       Rotational and irrotational flow.
•       One, two and three-dimensional flows.

Steady and Unsteady flow:

Steady flow is defined as that type of flow in which the fluid characteristics like velocity, pressure, density, etc. at a point do not change with time.

Unsteady flow is that type of flow, in which the velocity, pressure or density at a point changes with respect to time.

Uniform and Non-uniform flow:

Uniform flow is defined as that type of flow in which the velocity at any given time does not change with respect to space (i.e., length of direction of the flow).

Non-uniform flow is that type of flow in which the velocity at any given time changes with respect to space.

Laminar and Turbulent flow:

Laminar flow is defined as that type of flow in which the fluid particles move along well-defined paths or streamline and all the streamlines are straight and parallel.  Thus the particles move in laminas or layers gliding smoothly over the adjacent layers.  This type of flow is also called as streamline flow or viscous flow.

Turbulent flow is that type of flow in which the fluid particles move in zigzag way.  Due to the movement of fluid particles in a zigzag way, the eddies formation takes place which are responsible for high-energy loss.  For a pipe flow, the type of flow is determined by a non-dimensional number called the Reynold number.

If the Reynold number is less than 2000, the flow is laminar.  If the Reynold number is more than 4000, it is called turbulent flow.  It the Reynold number lies between 2000 and 4000, the flow may be laminar or turbulent.

Compressible and Incompressible flows:

Compressible flow is that type of flow in which the density of the fluid changes from point to point or in other words the density is not constant for the fluid.

Incompressible flow is that type of flow in which the density is constant for the fluid flow.  Liquids are generally incompressible while gases are compressible.

Rotational and Irrotational flows:

Rotational flow is that type of flow in which the fluid particles while flowing along streamlines also rotate about their own axis.

And if the fluid particles while flowing along the streamlines, do not rotate about their own axis that type of flow is called irrotational flow.

One, Two and Three-Dimensional flows:

One-dimensional flow is that type of flow in which the flow parameter such as velocity is a function of time and one space co-ordinate only.  For a steady one-dimensional flow, the velocity is a function of one-space-co-ordinate only.  The variation of velocities in other two mutually perpendicular directions is assumed negligible.

Two-dimensional flow is that type of flow in which the velocity is a function of time and two rectangle space co-ordinates.  For a steady two-dimensional flow the velocity is a function of to space co-ordinates only.  The variation of velocity in the third direction is negligible.

Three-dimensional is that type of flow in which the velocity is a function of time and three mutually perpendicular directions.  But for a steady three-dimensional flow the fluid parameters are functions of three space co-ordinates.