For a long time, the only way to test designs for aircraft was to actually fly them, tweak the design by experience in response to perceived problems and then fly them again. The advent of the wind tunnel added a new dimension to design testing but it was still time consuming and expensive. If only there were some way to put the Navier-Stokes used to approximate the flow of fluids to work on aircraft design, then rapid strides might be possible. It was the development of the computer that enabled this to happen. But the sheer amount of raw processing power and large physical memory that was required meant, before supercomputers, progress was slow. Now, faster processors, cheaper memory and low-cost 3D graphic cards mean that many CFD tasks can be performed on workstations or even PCs for relatively trivial problems. Although there will still be a need for supercomputers for the foreseeable future.

Through computers, Computational Fluid Dynamics turn the shape of the design model and the surrounding air into a patchwork of polyhedrons, each of which is represented by a set of mathematical equations. The flow going in or out of any one polyhedron is affected by the flow of its neighbours and so all the equations for all the polyhedrons must be solved simultaneously. Once the equations have been solved, the computer can also be used to assess the aerodynamic properties of the entire design.

The time saving aspect of CFD is spectacular, overnight assessments of aircraft are now possible instead of taking many months.