Forebody Articulation at High Angles of Incidence.

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Bibliographic Details
Title: Forebody Articulation at High Angles of Incidence.
Authors: Kumar, Roopesh1, Foster, Devon S.1, Kumar, Rajan1, Dickinson, Benjamin T.2
Source: AIAA Journal. Oct2023, Vol. 61 Issue 10, p4401-4418. 18p.
Abstract: An experimental investigation was carried out to understand the effect of forebody articulation on the aerodynamic characteristics and the flowfield development over a slender body at high angles of incidence. The experiments were carried out at the Florida A&M University and Florida State University low-speed wind tunnel over a range of forebody deflection (δ=0, ±10, and ±20 deg) and flow conditions. The results show that a positive forebody deflection increases the normal-force coefficient, whereas a negative forebody deflection decreases the normal-force coefficient at high angles of incidence. Pitching moment characteristics showed that all forebody deflections tested produce a pitching moment despite minimal normal force at low angles of incidence. Lateral aerodynamic characteristics showed that the side-force onset angle does not solely depend on the semi-apex angle of the forebody (as predicted for axisymmetric slender bodies), and the role of the forebody-to-aftbody transition geometry in initiating vortex asymmetry is equally important. The particle image velocimetry results show that a positive forebody deflection increases the size, strength, and circulation of the vortices developing on the body, leading to an increase in aerodynamic forces and moments. The flowfield development for a negative forebody deflection is dominated by secondary shear-layer vortices originating from the forebody to aftbody junction. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:An experimental investigation was carried out to understand the effect of forebody articulation on the aerodynamic characteristics and the flowfield development over a slender body at high angles of incidence. The experiments were carried out at the Florida A&M University and Florida State University low-speed wind tunnel over a range of forebody deflection (δ=0, ±10, and ±20 deg) and flow conditions. The results show that a positive forebody deflection increases the normal-force coefficient, whereas a negative forebody deflection decreases the normal-force coefficient at high angles of incidence. Pitching moment characteristics showed that all forebody deflections tested produce a pitching moment despite minimal normal force at low angles of incidence. Lateral aerodynamic characteristics showed that the side-force onset angle does not solely depend on the semi-apex angle of the forebody (as predicted for axisymmetric slender bodies), and the role of the forebody-to-aftbody transition geometry in initiating vortex asymmetry is equally important. The particle image velocimetry results show that a positive forebody deflection increases the size, strength, and circulation of the vortices developing on the body, leading to an increase in aerodynamic forces and moments. The flowfield development for a negative forebody deflection is dominated by secondary shear-layer vortices originating from the forebody to aftbody junction. [ABSTRACT FROM AUTHOR]
ISSN:00011452
DOI:10.2514/1.J062637