Nose Bluntness for Side Force Control on Circular Cones at High Incidence 2004-37

Kumar, R and Viswanath, P (2004) Nose Bluntness for Side Force Control on Circular Cones at High Incidence 2004-37. In: 42nd AIAA Aerospace Sciences Meeting and Exhibit, 5-8 January 2004, Reno, Nevada.

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    Abstract

    An experimental investigation has been carried out13; to study the effect of nose bluntness on the13; characteristics of vortex asymmetry and induced side13; forces on slender cone models at low speeds. Two cone13; models of semi-apex angle of 8xB0; and 12xB0; were utilized13; and on each model nose bluntness was varied upto 20%13; (based on base dia.). Measurements made consisted of13; six-component balance loads over a wide range of13; Reynolds number from 0.4 x 106 to 5.4 x 106. Limited13; studies involving pressure distribution on the 12xB0; cone13; model were also made. For each model configuration,13; roll search has been carried out leading to the13; identification of x201C;Stable roll positionx201D;. It has been13; demonstrated for the first time that onset of vortex13; asymmetry with nose blunting is practically13; independent of Reynolds number, suggesting13; domination of invisid flow mechanisms in triggering13; vortex asymmetry on blunted cones (like on pointed13; forebodies). The (max) side force levels decrease13; initially upto a certain bluntness ratio, then increase and13; followed by a gradual decrease for large values of13; bluntness ratios; this decrease or increase in side force13; levels with nose blunting is associated with a13; corresponding increase or decrease respectively in the13; onset of vortex asymmetry. While the increase in side13; force level beyond the first minimum is qualitatively13; similar to those observed in earlier studies, the present13; data definitely indicate that there is a progressive13; decrease in side force levels to relatively low values for13; large bluntness ratios, which could form an important13; design input. The bluntness ratio corresponding to the13; occurrence of the first minimum in (max.) side force13; depends on the cone angle and nearly independent of13; Reynolds number.13;

    Item Type: Conference or Workshop Item (Paper)
    Uncontrolled Keywords: vortex asymmetry;semi-apex angle
    Subjects: AERONAUTICS > Aeronautics (General)
    Division/Department: National Trisonic Aerodynamic Facility, National Trisonic Aerodynamic Facility
    Depositing User: Mr. N A
    Date Deposited: 25 Jan 2006
    Last Modified: 24 May 2010 09:39
    URI: http://nal-ir.nal.res.in/id/eprint/989

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