About CFD Analysis

At a fundamental level, Computational Fluid Dynamics analysis (CFD Analysis) is about the solution of equations that describe the flow of fluids (liquids and gases). These equations represent the conservation of physical quantities which include mass, energy and momentum. Because of their complexity the equations can only realistically be solved on computers running specialised software, thus the need for CFD Analysis.

The solutions of the equations are found at numerous points in the flow where each point is defined by its position in three-dimensional space. Usually solutions are obtained on a grid, or mesh, which defines the domain being modelled. A mesh will comprise a large number of computational elements or control volumes (also called cells). Where Computational Fluid Dynamics is employed, there are typically any number from a few tens of thousands to many millions of cells that will be defined.

The more cells, the greater the resolution of the CFD analysis: but the calculation will take longer to achieve a solution.

Steady state results can be obtained through iterative calculation or by continuing time-dependent simulation, but because of non-linearities in the equation-set the calculations will take many hours to reach a meaningful result. CFD analysis generates large amounts of data. With the aid of visualisation-software this data can be presented in image-form. Images will typically show flow patterns and distributions of important variables (velocity, pressure, temperature, etc). If time-dependent simulation is carried out (rather than steady-state analysis) the results can be presented as animations showing time-varying flow patterns and quantities. Such results will often provide insights into the structure of the flow; insights that are difficult to obtain by other means.

With rapid advances in computers, allied to developments in the underlying numerical-algorithms and software, CFD analysis is now widely used throughout industry. Applications include aerodynamics (aircraft, vehicles), process flows (chemical industry), medical science (blood flow in the body), indoor environment (comfort, air quality and safety) and wind flow in the urban environment. Many other uses exist – wherever liquids or gases are in motion. Applications in the construction and buildings field encompass: natural and mechanical ventilation of buildings, fire and smoke modelling, heating and cooling of spaces, prediction of wind environment around buildings, and industrial and process ventilation. In this field, the benefits of CFD analysis include: improved occupant comfort, safe escape in the event of fire, increased energy efficiency, successful operation of natural ventilation schemes, improved pedestrian environments within urban developments, and safe ventilation, for example, in laboratories and process environments.

Projects may last from a couple of days, for a small project, to a time scale of a number of weeks where a complex space or processes are being considered and detailed optimisations being carried out.

At its best, CFD analysis supplements existing knowledge and provides a means to evaluate design options, seeking to optimise against specified criteria.

To learn more about the ways in which we use CFD analysis, take a look at our case studies, or contact for more information about our Computational Fluid Dynamics projects that we have worked on.