Properties of fluid dynamics include velocity, pressure, density and temperature.

Fluids in the physical world obey several rules, including conservation of energy, conservation of momentum and conservation of mass. These laws state that the fluid has to have a constant mass, momentum and energy throughout its movements.

Fluids are described by Navier-Stokes (Claude-Louis Navier and George Gabriel Stokes) equations. They are a set of non linear partial differential equations that describe the flow. These equations can describe most of the flows of interest, but are very complex and take up a lot of computational processing. Thus when efficiency is required a reduced form of these equations was given by Osborne Reynolds, called the Reynolds-averaged Navier-Stokes(RaNS) equations.

To make these equations simpler, it is often the case that the fluid being described is broken down, and looked at for certain characteristics. If it can be described in more detail, it can often be the case that less needs to be known, or certain variables can actually be constants for that particular fluid flow.

Compressible Flow is where the density changes throughout the fluid.
Incompressible Flow is where the density changes are neglible and so the fluids density can be assumed constant throughout.

Viscous Flow is where friction has an affect on the fluid.
Inviscid Flow is where friction has no affect on the fluid. The standard equations for these types are Euler equations. The Reynolds number can be used to determine which of these should be used. The Reynolds number is the ratio of inertial forces to viscous forces.

Steady Flow is where the fluid is simplified so that all changes of fluid properties over time are set to zero. This simplifies the Navier-Stokes and Euler equations.
Unsteady Flow is where the fluid is not simplified and so still contains all the changes over time.

Turbulent Flow is dominated by recirculation, eddies and apparent randomness. It is represented by Reynolds decomposition which breaks the flow into steady and non steady components.
Laminar Flow is where no turbulence can be seen in the flow.

Newtonian Fluids are modelled by a viscosity coefficient which is dependant on the fluid.
Non-Newtonian Fluids are where the viscosity changes due to a shearing force.

If a fluid is Viscous, then it has a low Reynolds number, which must mean that that the fluid has a Laminar flow. This is characterised by a smooth, constant fluid motion.

On the other hand, if a fluid is Inviscid then it has a high Reynolds number, and a Turbulent flow. This leads to eddies, vortices and other fluid fluctuations.