Abstract:
The first part of this report describes the Ngh-speed tunnel installation in the Aerodynamics Division of the National Physical Laboratory. The installation consists of the 12-in. diameter High-Speed Tunnel, the 20 x 8-in. High-Speed Tunnel and a number of smaller tunnels all of which are operated on the induction principle from a common compressed-air storage capacity. An account is included of a series of experiments which were made to investigate the influence of the design on the efficiency of an induced-flow tunnel, and finally the new 18 × 14-in. High-Speed tunnel is described. The second part describes some of the experimental techniques which have been used. Many of these are similar in principle to those of low-speed tunnel practice, but some of them (e.g., the schlieren and shadowgraph techniques) are Peculiar to compressible-flow experiments. The third part of the report reviews the experimental results obtained in tile high-speed tunnels during and immediately before the war. The phenomena which occur on a particular aerofoil as the Maeh number is increased from a low value are described in detail and the effects of the aerofoil shape are then discussed. This approach is used also for supersonic flow where the flow round a particular aerofoil is again described in detail and the effects of aerofoil shape and. Mach number are discussed. The flow round an aerofoil with a control flap is discussed for both subsonic and supersonic flow and an account is included of a number of other fundamental and ad hoc investigations. The report was written in 1946 as a contribution to the series of monographs intended for the Scientific War Records.
