Instead, engineers employ computational codes that simplify effects. These simplifications are the reasons that comfortable conference rooms remain elusive. Though few of us notice air's movement unless it whips up into a wind or subsides into stillness, its flow follows complex paths. The complexity stems from a phenomenon called turbulence. But then, a smooth flow will develop instabilities that rapidly transition into turbulence.
Turbulent flow is random and chaotic.
Within a span of only a few millimeters, small, random fluctuations in a flow can spawn large vortices of turbulence. Think of what happens to smoke from a cigarette. It trails smoothly upwards for a little while, then suddenly bends and swirls in snakelike writhing. To predict precisely air's tortuous path, engineers would have to resolve a flow on a computational grid with zones fine enough to capture the minute fluctuations. Tafti likens the effect to taking all the frames of a motion picture and superimposing them to obtain a single frame that encapsulates the entire movie.