PIV measurement of separated flow in a square channel with streamwise periodic ribs on one wall
Author
Summary, in English
In. this study, particle image velocimetry (PIV) is used to investigate the physical process of separated flow in a square channel roughened with periodically transverse ribs on one wall. The ribs obstruct the channel by 15% of its height and are arranged 12 rib heights apart. The Reynolds number based on the bulk-mean velocity and the corresponding hydraulic diameter of the channel, is fixed at 22,000. Assuming flow periodicity in the streamwise direction, the investigated domain is between two consecutive ribs. The emphasis of this study is to give some insight into the turbulence mechanism associated with separation, reattachment, and subsequent redevelopment. Results are included for mean velocity, friction coefficient, vorticity thickness, Reynolds shear stress, anisotropy parameter and production of turbulent kinetic energy and shear stress. Based on the two-point correlation profiles, Taylor microscales are derived to reveal the sizes of the turbulence structure in the longitudinal and lateral directions. Moreover Galilean decomposition is applied to the instantaneous velocity fields. The result shows that the separated shear layer is dominated by the large-scale, unsteady vortical structures.
Department/s
Publishing year
2007
Language
English
Pages
834-841
Publication/Series
Journal of Fluids Engineering
Volume
129
Issue
7
Document type
Journal article
Publisher
American Society Of Mechanical Engineers (ASME)
Topic
- Energy Engineering
Keywords
- PIV
- turbulence properties
- separated flow
Status
Published
Research group
- heat transfer
ISBN/ISSN/Other
- ISSN: 0098-2202