Accession Number:

ADA179462

Title:

The Viscous Flow Induced Near a Wall by Counter-Rotating Vortex Pairs and Vortex Loops.

Descriptive Note:

Interim rept. Jul 83-Jul 85,

Corporate Author:

LEHIGH UNIV BETHLEHEM PA DEPT OF MECHANICAL ENGINEERING AND MECHANICS

Personal Author(s):

Report Date:

1985-06-01

Pagination or Media Count:

350.0

Abstract:

Vortex motion above walls is observed in a variety of physical situations this study the problem of how a viscous flow near a wall responds to the motion of certain vortex motions. Specifically the unsteady boundary layers induced by the motion of two dimensional rectilinear vortex pairs and three dimesional vortex loops in an otherwise stagnant fluid above a plane wall are considered numerical solutions are obtained for the evolution of the boundary layer flow as it develops under the influence of the moving vortices. All of the vortex flows considered in this study are related to more complex vortex flows observed in a diverse variety of physical situations many of these situations relate to the observed time-dependent flow in a turbulent boundary layer and are discussed. The boundary layer induced by a pair of counter rotating rectilinear vortices in motion above a plane in an otherwise stagnant fluid is addressed depending on the assumed sense of rotation the vortices either move toward or recede from the wall. A symmetric situation is considered where both vortices are equidistant from the wall. An symmetric situation is considered where a counter rotating pair approaches the wall at angle of attack. The motion of three-dimensional vortex loops which have a plane of symmetry is considered. A method is developed which allows the computation of the flow velocities on and near the symmetry plane of the loop. The computed results show a variety of complex three dimensional separation phenomena again the boundary layer solutions ultimately show strong localized growth and are suggestive that a boundary-layer eruption and strong viscous-inviscid interaction will occur.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE