Accession Number : ADA017039

Title :   Vortex Development and Breakdown.

Descriptive Note : Final rept. Apr 74-May 75,


Personal Author(s) : Raat,J.

Report Date : AUG 1975

Pagination or Media Count : 42

Abstract : 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.

Descriptors :   *Vortices, *Fluid dynamics, Dissipation, Viscous flow, Inviscid flow, Circulation, Compatibility, Axial flow, Mathematical prediction, Pressure gradients, Numerical methods and procedures, Velocity

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE