Fluid motion can take a variety of forms ranging from simple flows such
as laminar flow in a pipe, to more complex flows such
as vortex shedding behind cylinders, wave motion and turbulence.
It incorporates both liquid and gaseous flows. Many of the
different flow situations have been examined experimentally,
however it is advantageous to develop a numerical model capable of
simulating the many flow structures experienced in the motion of
different fluids.
Fluid motion is governed by the continuity equation
and the Navier-Stokes equation
for a fluid with velocity 
, density 
,
pressure p, kinematic shear viscosity 
and kinematic bulk viscosity
.
The Navier-Stokes equation is a second-order partial differential
equation which has no known analytic solution except for a small number
of special cases. With the advent of computer technology attempts have
been made at producing numerical simulations of fluid flows.
