Experimental Investigation of a Fin-cone Interference Flow Field at Mach 5


Book Description

The general purpose of this investigation was to study the separated flow field associated with a fin-body juncture. Specific objectives included: (a) determining the severity and extent of aerodynamic heating, (b) providing flow visualization results to illustrate the flow structure, and (c) obtaining a data base of heat-transfer and surface-pressure measurements upon which to develop future analytical relations to predict peak interference heating levels. Tests were conducted at Mach 5 over a unit Reynolds number range of 4.5 to 26 million per foot. A fin-cone model was used. The data consist of surface- pressure distributions, heat-transfer measurements using the phase-change paint technique, and schlieren and oil-flow photographs. Results are presented for several fin-cone geometries to include fin sweep and fin-cone gap. Where possible, comparisons are made with fin-flat-plate data.




Boundary Layer Effects


Book Description

In 1975 the U.S. Air Force and the Federal Republic of Germany signed a Data Exchange Agreement numbered AF-75-G-7440 entitled 'Viscous and Interacting Flow Fields.' The purpose was to exchange data in the area of boundary layer research. It includes both experimental and theoretical boundary layer research at speeds from subsonic to hypersonic Mach numbers in the presence of laminar, transitional, and turbulent boundary layers. The main effort in recent years has been on turbulent boundary layers, both attached and separated in the presence of such parameters as pressure gradients, wall temperature, surface roughness, etc. In the United States the research was conducted in various Department of Defense, NASA, aircraft corporations, and various university laboratories. In the Federal Republic of Germany it was carried out within the various DFVLR, industrial, and university research centers.




Scientific and Technical Aerospace Reports


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Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.




Use of Phase-change Paints to Study Fin-body Interference Heating


Book Description

In recent years the phase-change paint technique has evolved into an accepted diagnostic tool in high-speed wind-tunnel testing. This report documents use of the method at the Naval Surface Weapons Center, White Oak Laboratory, to study aerodynamic interference heating on fin-body configurations. Various aspects of both the underlying theory and the experimental method are enumerated based on experience and on information from other researchers. Analytic relationships are presented which indicate how uncertainties in the various input parameters affect the uncertainty in the heat-transfer coefficient. Advantages and disadvantages of the phase-change paint method are discussed.




Hypersonics


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Normal Impingement of a Supersonic Jet on a Plane


Book Description

The problem of a balanced, planar or axisymmetric, supersonic jet impinging normally on a flat surface has been considered based on an inviscid theory. The object of the study was to provide a rational model for calculating shock-interference heating as produced by a type IV shock-interaction pattern. The unwanted singularity at a low supersonic Mach number peculiar to scheme I of the one-strip formulation of the method of integral relations, as observed by South and by Gummer and Hunt, was successfully removed by the application of the scheme III of the one-strip formulation of the method of integral relations. The resulting simultaneous nonlinear algebraic equations were easily solved iteratively by the Newton-Raphson method. Sensitivity of the solution on various approximating functions employed was extensively investigated. Unlike the findings reported by Gummer and Hunt, solutions that satisfy all well-posed boundary conditions can be obtained by the one-strip formulation. Results indicate that, for the planar case, a rational engineering solution for the stagnation-point velocity gradient (and hence the peak heat-transfer rate) has been obtained. For the axisymmetric case, however, solutions appear to be not quite converging. A two-strip formulation based on the method of integral relations is also included.










NASA SP.


Book Description