Various Types of Flow
- Types of flow
1. Uniform/Non-uniform flow
2. Steady/Unsteady flow
3. Laminar/Turbulent flow
4. Compressible/ Incompressible flow
5. Viscous/Non viscous flow
In Details :-
1. Uniform/Non-uniform flow
A flow is said to be uniform if velocities at different points along a streamline in a flow field at an instant are same both in magnitude and direction, i.c., velocity does not vary with space. If change occurs either in magnitude or direction or both then the flow is said to be non-uniform.
2. Steady/Unsteady flow
When there is no change in flow parameters (velocity, pressure of fluid) with respect to time at a point, then the flow is said to be steady. Variations in parameters with time make the flow unsteady.
3. Laminar flow/Turbulent flow
In a laminar flow the fluid particles move in layers without interfering with the motion of fluid particles in the adjacent layers. A turbulent flow is a disturbed flow in which there are random velocity fluctuations on top of the average flow. Turbulent flow occurs when the flow velocity is high and the particles no longer flow smoothly in layers and turbulence effect occurs.
In a turbulent flow, inspite of random variations of velocity and pressure at a point, it is possible that a distinct statistical average value of these variables exists. The instantaneous velocity and pressure at a point fluctuate above a mean value with respect to time.
4. Compressible/ Incompressible flow
When the density of the fluid varies with pressure it is termed as compressible flow. Otherwise it is incompressible. Flow of air through a ventilator can be treated as incompressible but under larger pressures difference it becomes compressible.
5. Viscous/Non-viscous flow
When the viscosity of the fluid is zero, it is termed as non-viscous otherwise it is viscous. Often analysis of fluid flow is done assuming an ideal fluid and then an emperical correction is applied to account for the effect of viscosity. Coefficient of discharge used in obstruction meters is one such empirical correction.
