Encyclopaedia Index

Introduction to Computational Fluid Dynamics


What is fluid flow?

Fluid flow is:


What is CFD?

CFD is predicting what will happen, quantitatively, when fluids flow, often with the complications of:

Click here to see some examples of CFD predictions


How old is CFD?

Its early beginnings were in the 1960's.


What use is CFD?

Knowing how fluids will flow, and what will be their quantitative effects on the solids with which they are in contact, assists:-

CFD-based flow simulations enable:-

Within a few years, it is to be expected, surgeons will conduct operations which may affect the flow of fluids within the human body (blood, urine, air, the fluid within the brain) only after their probable effects have been predicted by CFD methods.


How does CFD make predictions?

CFD uses a computer to solve the relevant science-based mathematical equations, using information about the circumstances in question.

Its components are therefore:



Can CFD be trusted?

Click here to read a more extended discussion of validation

CFD-based predictions are never 100%-reliable, because:

The reliability is greater:

- for laminar flows rather than turbulent ones

- for single-phase flows rather than multi-phase flows;

- for chemically-inert rather than chemically-reactive materials;

- for single chemical reactions rather than multiple ones;

- for simple fluids rather than those of complex composition.

Therefore, coal-fired furnaces represent an extreme of uncertainty; but CFD is nevertheless used increasingly in their design because the uncertainties resulting from its non-use is even greater.

  Click here to see some "validation" results

Click here for a more extended account of what CFD can and cannot do


How does one become a CFD User?

In the past, there have been three methods for obtaining the benefits of CFD:

  1. Purchase (or rent) a suitable computer code, and learn how to use it for yourself.
  2. Hire a consultant to use the code for you and to provide you with the results of the predictions.
  3. Avail yourself of remote computing power, and expertise, via Internet.

However, nowadays there are intermediate methods also.

Click here to see the spectrum of services offered by CHAM


Where do CHAM, and PHOENICS, fit in?

- simultaneous stresses in solids;

- multi-fluid turbulence models;

- the LVEL and IMMERSOL models for interspersed solids and fluids;

- the virtual-reality user interface;

- use via Internet ; etc.

However, CHAM also includes public-domain models and features which it has not invented, if its users appear to want them. This is why PHOENICS has more models of turbulence and two-phase flow than any other code on the market.


The PHOENICS computer-code family.

- FLAIR for heating and ventilating of buildings;

- HOTBOX for electronics-cooling applications;

- CVD for chemical-vapour-deposition reactors;

Click here for more information