A fluid in motion is said to be flowing.
We can use streamlines to visualise flow of fluids (they actually are the just the field lines to the velocity vector field), similar to how field lines are used to visualise Electric Fields and Magnetic Fields.
The density of streamlines in a fluid is proportional to the velocity of the fluid.
Definition
Flow of a fluid:
Properties
Laminar/Turbulent Flow
A fluid flowing at a constant velocity everywhere is said to have a laminar flow.
Conversely, a fluid which doesn’t have constant smooth velocity everywhere is said to have turbulent flow.
Compressible/Incompressible Flow
A fluid retains it’s density while flowing. For an incompressible fluid, this means that the volume of the fluid also remains the same.
Incompressible flow relates to vector fields: The flow of a fluid is incompressible iff its velocity vector field is an incompressible vector field.
Rotational/Irrotational Flow
In rotational flow, each of the fluid particles undergo rotational torque as they move. In irrotational flow, this is absent.#tosee
Ideal Fluid
An ideal fluid is one defined to be incompressible. It’s flow is defined to be laminar, incompressible, nonviscous and irrotational !