Accession Number:

ADA300023

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):

Report Date:

1995-09-24

Pagination or Media Count:

39.0

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.

Subject Categories:

  • Aerodynamics
  • Fluid Mechanics
  • Helicopters

Distribution Statement:

APPROVED FOR PUBLIC RELEASE