A visualization study of fluid-structure interaction between a circular cylinder and a channel bed

Flow visualization was used to study the fluid-structure interaction between a circular cylinder and a shallow turbulent open channel flow. The Reynolds number ranged from ReD= 1500–4400 based on the cylinder diameter, and from ReH=7,800−27,600 based on the channel hydraulic radius. The cylinder was mounted vertically on the channel bed and the flow depth-to-cylinder-diameter ratio was varied fromd/D=7.0−11.7. Tests were carried out over smooth and rough beds, with the rough beds being either permeable or impermeable. The study showed that the horseshoe vortex forming at the cylinder-bed junction affects many of the flow structures, including the mode of vortex shedding, the shear layer dynamics, the vortex formation length, and the width of the near-wake region. The influence of the horseshoe vortex can be recognized throughout the depth of flow; however, its influence decreases with an increase in distance from the channel bed. It was also possible to discern that the bed roughness resulted in a change to the above interaction and the permeability of the bed resulted in additional changes.

[1]  Characteristics of shallow turbulent near wakes at low Reynolds numbers , 2000 .

[2]  S. Szepessy,et al.  On the spanwise correlation of vortex shedding from a circular cylinder at high subcritical Reynolds number , 1994 .

[3]  W. Graf,et al.  TURBULENT BOUNDARY-LAYER FLOW OVER PERMEABLE AND NON-PERMEABLE ROUGH SURFACES , 1983 .

[4]  Donald Rockwell,et al.  Instantaneous Structure of the Near-Wake of a Circular Cylinder: on the Effect of Reynolds Number , 1995 .

[5]  I.Istiarto,et al.  Eksperiments on flow Around a Cylinder in a scoured Channel Bed , 2001 .

[6]  T. Morel,et al.  Effect of free stream turbulence on the flow around bluff bodies , 1983 .

[7]  M. P. Païdoussis,et al.  FLUID BEHAVIOUR OF SIDE-BY-SIDE CIRCULAR CYLINDERS IN STEADY CROSS-FLOW , 1999 .

[8]  R. French.  Open Channel Hydraulics , 1985 .

[9]  Vladimir Nikora,et al.  Spatially Averaged Open-Channel Flow over Rough Bed , 2001 .

[10]  C. R. Smith,et al.  Secondary vortices in the wake of circular cylinders , 1986, Journal of Fluid Mechanics.

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

[12]  Ram Balachandar,et al.  A Study on Turbulent Boundary Layers on a Smooth Flat Plate in an Open Channel , 2001 .

[13]  Concentration Profiles in Shallow Turbulent Wakes , 1999 .

[14]  Ram Balachandar,et al.  Rough wall turbulent boundary layers in shallow open channel flow , 2000 .

[15]  D. Rockwell,et al.  Control of vortex formation from a vertical cylinder in shallow water: Effect of localized roughness elements , 2002 .

[16]  Y. Zech,et al.  Flow around a cylinder: Shallow-water modeling with diffusion-dispersion , 1998 .

[17]  V. C. Patel,et al.  Rough Wall Boundary Layer on Plates in Open Channels , 2002 .

[18]  Ram Balachandar,et al.  Turbulent Boundary Layers in Low Reynolds Number Shallow Open Channel Flows , 1999 .

[19]  Peter W. Bearman,et al.  Aspect ratio and end plate effects on vortex shedding from a circular cylinder , 1992, Journal of Fluid Mechanics.

[20]  R. A. Antonia,et al.  Surface roughness effects in turbulent boundary layers , 1999 .

[21]  Owen M. Griffin,et al.  Vortex Shedding From Bluff Bodies in a Shear Flow: A Review , 1985 .

[22]  D. Bergstrom,et al.  Skin Friction Correlation in Open Channel Boundary Layers , 2001 .

[23]  Kenneth V. H. Smith,et al.  Channel Flow Over Permeable Beds of Graded Spheres , 1976 .

[24]  G. Paudyal,et al.  Characteristics of free surface flow over gravel bed , 1985 .

[25]  Donghuo Zhou,et al.  Effects of Porous Bed on Turbulent Stream Flow above Bed , 1992 .

[26]  B. Dargahi.  The turbulent flow field around a circular cylinder , 1989 .

[27]  Jørgen Fredsøe,et al.  Hydrodynamics Around Cylindrical Structures , 2006 .

[28]  A. Grass.  Structural features of turbulent flow over smooth and rough boundaries , 1971, Journal of Fluid Mechanics.

[29]  D. Bergstrom,et al.  Application of power laws to low Reynolds number boundary layers on smooth and rough surfaces , 2001 .

[30]  Peter Freymuth,et al.  The vortex patterns of dynamic separation: A parametric and comparative study , 1985 .

[31]  C. Norberg.  Interaction between freestream turbulence and vortex shedding for a single tube in cross-flow , 1986 .

[32]  Subhasish Dey,et al.  TIME-VARIATION OF SCOUR IN THE VICINITY OF CIRCULAR PIERS. , 1999 .

[33]  Nallamuthu Rajaratnam,et al.  Flow around bridge piers , 1998 .

[34]  C. Williamson.  Vortex Dynamics in the Cylinder Wake , 1996 .