Accession Number : AD0604036

Title :   THE EFFECT OF SURFACE PERTURBATIONS ON THE PRESSURE DISTRIBUTIONS ABOUT BLUNT TWODIMENSIONAL BODIES AT HIGH MACH NUMBERS,

Corporate Author : AERONAUTICAL RESEARCH ASSOCIATES OF PRINCETON INC N J

Personal Author(s) : Donaldson,Coleman duP. ; Sullivan,Roger D. ; Hayes,Wallace D.

Report Date : APR 1964

Pagination or Media Count : 104

Abstract : A method which is simpler and easier to apply than the general method of characteristics is developed for computing the pressure distributions about blunt bodies at high Mach number. The method presented enables one to compute the change in pressure distribution that results when a basic shape whose pressure distribution and flow field are known is perturbed in some manner, either by deflection of a control surface or by an aeroelastic deformation. In order to illustrate the character of this perturbation problem, the linearized theory of the pressure distribution upon a perturbed flat plate above which exists an entirely supersonic entropy layer is developed in some detail and applied to the special case of the computation of flap effectiveness on blunt wedge airfoils at infinite Mach number. With the background of these results from the linearized theory, the more general problem is discussed and an empirical method is suggested for computing the pressure distribution about a perturbed basic shape whose pressure distribution and flow field are known. The method is then used to compute the pressure distribution about a blunt two-dimensional airfoil for which theoretical and experimental pressure distributions have been obtained at M = 5 and M = approx. 8. Comparison of the method with both exact theory and experimental results shows satisfactory agreement for this particular case. (Author)

Descriptors :   (*BLUNT BODIES, PRESSURE), (*AIRFOILS, PRESSURE), HYPERSONIC FLOW, DISTRIBUTION, AERODYNAMIC CONTROL SURFACES, AEROELASTICITY, FLAT PLATE MODELS, FLAPS(CONTROL SURFACES), WEDGES, SURFACE PROPERTIES

Distribution Statement : APPROVED FOR PUBLIC RELEASE