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Vortex Development and Breakdown.
Final rept. Apr 74-May 75,
GENERAL DYNAMICS/CONVAIR SAN DIEGO CALIF
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A line vortex is assumed to consist of a thin viscous core of laminar embedded in an inviscid flow of uniform circulation and with axial velocity that may depend upon the distance along the core. Self-similar solutions are obtained for the particular case of an external velocity inversely proportional to the core length. These solutions exhibit linear core growth. The primary mechanism of vortex breakdown is discussed involving a fundamental incompatibility of the axial and azimuthal flow modes within the confines of a thin layer. A quantitative method is developed to predict the breakdown point in terms of initial and external aerodynamic conditions. Breakdown diagrams pertaining to flow mode incompatibility are presented for a particular family of initial core velocity profiles. Numerical examples exhibit the effect of external pressure gradients.
APPROVED FOR PUBLIC RELEASE