The development of slotted working-section liners for transonic operation of the R.A.E. Bedford 3-ft wind tunnel

Abstract

The development of removable slotted liners to extend the range of the Royal Aircraft Establishment 3-ft Supersonic Wind Tunnel at Bedford to transonic speeds is described. The liners are mounted within the existing working-section on the two sides, enclosing shallow outer chambers between their slotted surfaces and the original side walls. At all speeds there was originally a pronounced streamwise pressure gradient, associated with reversed flows in the outer chambers. It was almost eliminated by the addition of perforated screens behind the slots to suppress turbulent mixing there.