I.1 What is CFD and Why?

Computational Fluid Dynamics is the use of computers to study fluid dynamics. The motion of fluids is described by the Navier-Stokes equations, which are a set of coupled 2nd order Partial Differential Equations involving the variables p and , which express the concepts of conservation of mass and momentum.

The NSE’s are

• 4 equations for 4 unknowns,
• coupled,
• non-linear,
• and often involve complex geometries.

For these reasons, it is rarely possible to find analytical solutions, and thus we must use computers to solve the equations. In addition, the flow problems we want to solve often include additional effects, eg. combustion, which involves additional modelling.