Turbulent flow in a ribbed channel: Flow structures in the vicinity of a rib

PIV measurements are performed in a channel with periodic ribs on one wall. The emphasis of this study is to investigate the flow structures in the vicinity of a rib in terms of mean velocitie s, Reynolds stresses, probability density functions (PDF) , and two-point correlations. The PDF distribution of u 0 is bimodal in the separated shear layer downstream of the rib. The maximum Reynolds shear stresses occur at the leading edge of the rib. Based on quadrant analysis, it is found that ejection motions make a dominant contribution to the Reynolds shear stress in this region. Moreover, topology-based visualization is applied to the sep aration bubble upstream of the rib. Salient critical points and limit cycle s are extracted, which gives clues to the physical processes occurring in the flow.

[1]  Lei Wang,et al.  PIV Measurement of Separated Flow in a Square Channel With Streamwise Periodic Ribs on One Wall , 2007 .

[2]  W. Willmarth,et al.  Structure of the Reynolds stress near the wall , 1972, Journal of Fluid Mechanics.

[3]  P. Holmes,et al.  The Proper Orthogonal Decomposition in the Analysis of Turbulent Flows , 1993 .

[4]  T. Arts,et al.  The Effect of Periodic Ribs on the Local Aerodynamic and Heat Transfer Performance of a Straight Cooling Channel , 1996 .

[5]  V. C. Patel,et al.  Large-eddy simulation of turbulent flow in a channel with rib roughness , 2003 .

[6]  R. Antonia,et al.  Structure of turbulent boundary layers on smooth and rough walls , 1994, Journal of Fluid Mechanics.

[7]  M. S. Chong,et al.  A Description of Eddying Motions and Flow Patterns Using Critical-Point Concepts , 1987 .

[8]  Roger D. Sullivan,et al.  A Two-Cell Vortex Solution of the Navier-Stokes Equations , 1959 .

[9]  Paolo Orlandi,et al.  Direct numerical simulations of turbulent channel flow with transverse square bars on one wall , 2003, Journal of Fluid Mechanics.

[10]  Characteristics of ejections in turbulent channel flow , 1987 .

[11]  Tony Arts,et al.  The Effect of Periodic Ribs on the Local Aerodynamic and Heat Transfer Performance of a Straight Cooling Channel , 1996 .

[12]  P. Bradshaw,et al.  The reattachment and relaxation of a turbulent shear layer , 1972, Journal of Fluid Mechanics.

[13]  Z. C. Liu,et al.  Analysis and interpretation of instantaneous turbulent velocity fields , 2000 .

[14]  T. Mullin,et al.  INTERMITTENT PHENOMENA IN THE FLOW OVER A RIB ROUGHENED SURFACE , 1991 .

[15]  C. Tropea,et al.  The Flow Around Surface-Mounted, Prismatic Obstacles Placed in a Fully Developed Channel Flow (Data Bank Contribution) , 1993 .

[16]  F. De Gregorio,et al.  Spatial resolution of PIV for the measurement of turbulence , 2007 .

[17]  Propagation velocity and space-time correlation of perturbations in turbulent channel flow , 1992 .

[18]  J. Chou,et al.  Branching of a horseshoe vortex around surface-mounted rectangular cylinders , 2000 .

[19]  J. Burgers.  A mathematical model illustrating the theory of turbulence , 1948 .