Accession Number : AD0703240

Title :   TURBULENT BOUNDARY-LAYER SEPARATION INDUCED BY THREE-DIMENSIONAL PROTUBERANCES.

Descriptive Note : Technical memo.,

Corporate Author : JOHNS HOPKINS UNIV SILVER SPRING MD APPLIED PHYSICS LAB

Personal Author(s) : Lucero,E. F.

Report Date : JAN 1970

Pagination or Media Count : 74

Abstract : The report presents the results of an experimental investigation on the extent of separation of a turbulent boundary layer due to cylindrical protuberances, square prisms, and triangular prisms mounted on a flat plate. The effect of the separated flow on the pressure distribution along the centerline of the plate and on the surface of the attached protuberances is shown. The widths of the protuberances were 0.6 and 1.0 inch, and the ratio of protuberance height to boundary-layer thickness, h/sigma, ranged from 0.3 to 4.4. The test Mach number was 2.17, and the unit Reynolds number was 3,000,000/ft. Results from the experiment indicate that: (1) when h/sigma, the extend of separation is dependent on protuberance height and on the diameter of the cylinder or the breadth of the square prism, but when h/sigma < or = 0.6 or when a triangular prism is used, no separation occurs; (2) the root pressure coefficient exceeds the plateau pressure coefficient by as much as 33% in the cases where the boundary layer does not separate; (3) a linear correlation exists between the initial-pressure-rise distance and the protuberance height; and (4) the cylinder stagnation pressures do not show a significant dependence on cylinder height for h/sigma < or = 1.80. (Author)

Descriptors :   (*TURBULENT BOUNDARY LAYER, *FLOW SEPARATION), FLAT PLATE MODELS, AIRCRAFT PROTUBERANCES, CYLINDRICAL BODIES, PRISMATIC BODIES, PRESSURE, DISTRIBUTION, REYNOLDS NUMBER, AERODYNAMIC CONFIGURATIONS

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE