In order to solve the governing equations of the fluid motion, first their numerical
analogue must be generated. This is done by a process referred to as discretization. In the
discretization process, each term within the partial differential equation describing the
flow is written in such a manner that the computer can be programmed to calculate.
There are various techniques for numerical discretization. Here we will introduce three
of the most commonly used techniques, namely: (1) the finite difference method, (2) the
finite element method and (3) the finite volume method. Spectral methods are also used
in CFD, which will be briefly discussed.