This elementary lecture introduces the idea of real-time computational simulation of fluid flow around an aircraft. It leads, through some initial naive assumptions, to the conclusion that this problem is not computable with any technology, due to nonnegotiable physical constants like the speed of sound in the atmosphere and the speed of electronic signals (close to the speed of light) in semiconductors. As the naive assumptions are replaced with more practical compromises, involving computer architecture and mathematical modeling, a computable problem comes into view. The presentation touches upon the discretization of a continuous mathematical problem and the distribution of a computation over the processors of a large-scale parallel computer. To illustrate, some videotaped comparisons are shown between computations and windtunnel experiments of vortical flows over delta-wing aircraft.

The presentation requires an overhead slide projector and a VHS VCR system to play the videos.