Generation and Management of Swirling Flows in Confined Streams.
Abstract
An experimental investigation of techniques for generating, measuring and controlling swirling flows in confined streams has been carried out. Several typical swirling flows were generated and their careful calibration was carried out using hot-wire anemometers and miniature vane-vorticity indicators. By inserting in these flows various flow manipulators, such as honeycombs, screens and perforated plates, a comparison of the characteristics of the flow downstream of the manipulators (e.g., distribution of streamwise vorticity) to the original test flows provided a measure of the effectiveness of the manipulators in suppressing large scale vorticity as well as clues to dominant mechanism of the flow transformations. It has been found that the effectiveness of a manipulator in suppressing the swirl conditions is reduced somewhat as the strength of the swirl upstream of it is increased, and is improved as the width of the vortex is increased while its strength remains the same. Although honeycombs have a high efficiency in suppressing swirl, their optimum mesh depends on the size of the swirl. The pressure drop across the manipulator, which plays an important role in design of wind tunnels and flow ducts, appears to play a minor role in the management of swirling flows. Recommended procedures for control of large scale swirling and secondary flows are developed, and general concepts are obtained which design and test engineers can adapt for 'tailoring and manipulating' their own special flows with different rotational characteristics. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1976
- Accession Number
- ADA029418
Entities
People
- H. M. Nagib
- Mahmoud Ahmed
- R. A. Wigeland
Organizations
- Illinois Institute of Technology