Disturbances from Ventilated Tunnel Walls in Aerofoil Testing,
ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)
Pagination or Media Count:
Evidence is presented which indicates that inflow through the slots of a slotted walled wind tunnel, when testing an aerofoil at conditions similar to those found in flight on wings, can penetrate into the tunnel flow to an extent which makes the determination of suitable homogeneous boundary conditions very difficult. Measurements show that the flow field generated by a lifting aerofoil causes low energy air from the plenum chamber to be drawn into the wind tunnel through the slots in the region of the upper surface to the aerofoil and that this air spreads into the working section downstream of the aerofoil. Suggestions are made for avoiding the difficulty in any future design wind tunnel.