Accession Number : AD0662965

Title :   SOME FACTORS CONTRIBUTING TO SCALE EFFECT AT SUPERSONIC SPEEDS,

Corporate Author : ADVISORY GROUP FOR AERONAUTICAL RESEARCH AND DEVELOPMENT PARIS (FRANCE)

Personal Author(s) : Abbott,Ira H.

Report Date : 1967

Pagination or Media Count : 28

Abstract : Considerable progress was made in the theory of the compressible laminar boundary layer, leading to predictions of skin friction and heat transfer, but experimental data are needed for verification. The theory of the compressible turbulent boundary layer is in an unsatisfactory state even for the simple case of no heat transfer, but experimental data are available at Mach numbers up to 4.5. The effects of heat transfer on turbulent skin friction are only qualitatively understood and the need is great for both theoretical and experimental research. It appears that the effect of surface roughness on turbulent skin friction at low supersonic Mach numbers is similar to that at subsonic speeds. It is indicated that the Reynolds number of transition from laminar to turbulent flow may be severely limited in supersonic wind tunnels by weak disturbances originating on the walls as well as by airstream turbulence and that extreme care is required to obtain sufficiently accurate nozzles to permit extensive laminar flow. The strong stabilizing effect on the laminar boundary layer of heat transfer from the air to the wall as predicted by Lees and Van Driest appears to be qualitatively confirmed when the disturbances are small. (Author)

Descriptors :   (*SUPERSONIC FLIGHT, SKIN FRICTION), (*BOUNDARY LAYER, SUPERSONIC FLOW), LAMINAR BOUNDARY LAYER, TURBULENT BOUNDARY LAYER, HEAT TRANSFER, SURFACE ROUGHNESS, REYNOLDS NUMBER

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE