Accession Number : ADA300513

Title :   The Fluid Mechanics of Vortex Cutting by a Blade.

Descriptive Note : Final rept. 1 Aug 92-31 Jul 95,

Corporate Author : IOWA STATE UNIV IOWA CITY

Personal Author(s) : Marshall, Jeffrey S.

PDF Url : ADA300513

Report Date : 30 SEP 1995

Pagination or Media Count : 39

Abstract : A study of the fluid dynamics associated with impact of a vortex on a body (such as a blade) moving normal to the vortex axis was performed. The physical features of the flow evolution were categorized in terms of two dimensionless parameters which represent a ratio of length scales and a ratio of velocity scales associated with the vortex core and with the body. Models of various features of the flow evolution are constructed and compared against experimental and detailed computational data. Primary features of interest in the study include vortex deflection and axial flow in the vortex core resulting from stretching by the blade, intense vorticity deformation resulting from penetration of the body into the vortex core (and resulting force on the body), traveling vortex breakdown formed immediately following vortex cutting by the body, and interaction of shed vorticity from the body with the primary vortex.

Descriptors :   *COMPUTATIONAL FLUID DYNAMICS, *ROTOR BLADES(ROTARY WINGS), *VORTEX SHEDDING, VELOCITY, MATHEMATICAL MODELS, DEFORMATION, BOUNDARY LAYER, VORTICES, HELICOPTER ROTORS, FLOW FIELDS, PENETRATION, APPROXIMATION(MATHEMATICS), BUBBLES, AERODYNAMIC FORCES, INVISCID FLOW, PRESSURE DISTRIBUTION, GAS SURFACE INTERACTIONS, POTENTIAL FLOW, AXIAL FLOW.

Subject Categories : Aerodynamics
      Fluid Mechanics
      Helicopters

Distribution Statement : APPROVED FOR PUBLIC RELEASE