Accession Number:

ADA280504

Title:

Vortex Tubes in Turbulent Flows: Identification, Representation, Reconstruction

Descriptive Note:

Contractor rept.

Corporate Author:

INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA

Personal Author(s):

• Banks, David C.
• Singer, Bart A.

Report Date:

1994-04-01

Pagination or Media Count:

17.0

Abstract:

In many cases the structure of a fluid flow is well-characterized by its vortices, especially for the purpose of visualization. In this paper we present a new algorithm for identifying vortices in complex flows. The algorithm produces a skeleton line along the center of a vortex by using a two-step predictor-corrector scheme. The vorticity vector field serves as the predictor and the pressure gradient in the perpendicular plane serves as the corrector. We describe an economical description of the vortex tubes cross-section a 5- term truncated Fourier series is generally sufficient, and it compresses the representation of the flow by a factor of 4000 or more. We reconstruct the vortex tubes as generalized cylinders, providing a polygonal mesh suitable for display on a graphics workstation. We show how the reconstructed geometry of vortex tubes can be enhanced to help visualize helical motion in a static image. Vortex, Visualization.

Descriptors:

• *TURBULENT FLOW
• *VORTICES
• *HILSCH TUBES
• *FLOW VISUALIZATION
• PRESSURE GRADIENTS
• ALGORITHMS
• FLOW FIELDS
• STATICS
• FOURIER SERIES
• PRESSURE DISTRIBUTION
• CROSS SECTIONS
• MESH
• IMAGE PROCESSING
• GRIDS
• MOTION

Subject Categories:

• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE