PIV Measurement of Separated Flow in a Square Channel With Streamwise Periodic Ribs on One Wall

[+] Author and Article Information
Lei Wang

Heat Transfer Division, Lund University, Box 118, SE-221 00, Lund, Sweden

Jiri Hejcik

Faculty of Mechanical Engineering, Brno University of Technology, 616 69, Brno, Czech Republic

Bengt Sunden1

Heat Transfer Division, Lund University, Box 118, SE-221 00, Lund, SwedenBengt.Sunden@vok.lth.se


Corresponding author.

J. Fluids Eng 129(7), 834-841 (Jan 04, 2007) (8 pages) doi:10.1115/1.2742723 History: Received March 17, 2006; Revised January 04, 2007

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.

Copyright © 2007 by American Society of Mechanical Engineers
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
Figure 1

Sketch of experimental setup

Grahic Jump Location
Figure 2

Rib configuration and measurement planes: (a) vertical symmetry plane and (b) horizontal plane

Grahic Jump Location
Figure 3

Streamlines of the mean flow

Grahic Jump Location
Figure 4

Skin-friction coefficient along the ribbed wall

Grahic Jump Location
Figure 5

Mean streamwise velocity profiles

Grahic Jump Location
Figure 6

Mean vertical velocity at y∕e=1.1

Grahic Jump Location
Figure 7

Visualization of vortices; the reference frame velocity is Uf=5.0m∕s(0.52Ur)

Grahic Jump Location
Figure 8

Visualization of vortices; the reference frame velocity is Uf=3.7m∕s(0.38Ur)

Grahic Jump Location
Figure 9

Vorticity thickness growth along the separated shear layer

Grahic Jump Location
Figure 10

Reynolds shear stress profiles

Grahic Jump Location
Figure 11

Maximum shear stress distribution

Grahic Jump Location
Figure 12

Anisotropy parameter

Grahic Jump Location
Figure 13

Turbulent kinetic energy production

Grahic Jump Location
Figure 14

Reynolds shear stress production

Grahic Jump Location
Figure 15

Spanwise u′ correlation coefficient at different points (x∕e,y∕e) in the flow field: A (0.5, 1), B (5.5, 2), C (5.5, 1), and D (8, 1)

Grahic Jump Location
Figure 16

Streamwise u′ correlation coefficient

Grahic Jump Location
Figure 17

Streamwise w′correlation coefficient

Grahic Jump Location
Figure 18

Mean velocity vector plot near the ribbed wall

Grahic Jump Location
Figure 19

Mean reattachment length in the spanwise direction



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In