The regulation of a wind tunnel system using minimum control effort is cons
idered. A theory enabling input-output models to be employed in the design
process is outlined. The procedure is applied to the regulation of the airs
peed within the tunnel working section enabling turbulent conditions to be
replicated, using a Dryden wind gust generator. Optimum dynamic control wit
h least control effort is achieved using a simple closed-loop structure. Th
e penalties involved in selecting a non-optimum design are commented on.