Control of Vortex Shedding of Circular Cylinder in Shallow Water Flow Using an Attached Splitter Plate

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Huseyin Akilli ◽  
Cuma Karakus ◽  
Atakan Akar ◽  
Besir Sahin ◽  
N. Filiz Tumen
Keyword(s):  
Circular Cylinder ◽  
Shallow Water ◽  
Water Flow ◽  
Vortex Shedding ◽  
Flow Characteristics ◽  
Splitter Plate ◽  
Wake Flow ◽  
Flow Data ◽  
Shallow Water Flow ◽  
Plate Length

In the present work, passive control of vortex shedding behind a circular cylinder by splitter plates of various lengths attached on the cylinder base is experimentally investigated in shallow water flow. Detailed measurements of instantaneous and time-averaged flow data of wake flow region at a Reynolds number of Re=6300 were obtained by particle image velocimetry technique. The length of the splitter plate was varied from L∕D=0.2 to L∕D=2.4 in order to see the effect of the splitter plate length on the flow characteristics. Instantaneous and time-averaged flow data clearly indicate that the length of the splitter plate has a substantial effect on the flow characteristics. The flow characteristics in the wake region of the circular cylinder sharply change up to the splitter plate length of L∕D=1.0. Above this plate length, small changes occur in the flow characteristics.

Wake Flow Behind a Cylinder With a Detached Splitter Plate

2005 ◽  
Author(s):  
Minter Cheng
Keyword(s):  
Strouhal Number ◽  
Vortex Shedding ◽  
Formation Process ◽  
Vortex Formation ◽  
Splitter Plate ◽  
Wake Flow ◽  
Plate Length ◽  
Splitter Plates ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency

Fluid flow across a bluff body can induce a series alternating vortices in the downstream flow field. The vortex flow can produce adverse effects on many engineering applications. A number of studies have shown that the wake splitter plate is one of the means to stabilize the vortex formation process. However, most of the previous studies are confined to cylinders with attached splitter plates. Very few studies investigate the effects of the spacing between the cylinder and the splitter plate on the formation of wake vortices. In the present study, the effects of the splitter plate length as well as the gap distance between the splitter plate and the cylinder on the wake flow behind a cylinder have been studied experimentally for low Reynolds number of 400. Both circular and square cylinders are studied in this research. Four splitter plates with different length, 1 ≤ L/D ≤ 4, have been used and a range of cylinder and splitter plate gap distance, 0 < G/D < 6, have been studied. By using flow visualization technique and hot-film anemometer measurement, detailed measurements of the velocity distribution, the vortex shedding frequency, the wake width, and the wake formation length are carried out in order to get a clear understanding of the flow interference behavior. The experimental results indicate that splitter plates alter the vortex formation process in the wake causing a decrease in vortex shedding frequency. The Strouhal number decreases with increasing the splitter plate length as well as the gap distance between the cylinder and the splitter plate. It is shown that a jump in Strouhal number occurs at G/D of 3 to 6. The jump is splitter plate length dependent, and generally the gap distance at which jump takes place increases as the splitter plate length increases.

Effect of Inclination Angle of Splitter Plate on Flow Over a Circular Cylinder

2011 ◽  
Author(s):  
Li Zhang ◽  
Lin Ding
Keyword(s):  
Circular Cylinder ◽  
Strouhal Number ◽  
Inclination Angle ◽  
Vortex Shedding ◽  
Lift Coefficient ◽  
Reynolds Numbers ◽  
Splitter Plate ◽  
Plate Length ◽  
Pressure Distributions ◽  
Vortex Shedding Frequency

Two-dimensional unsteady laminar flow over a circular cylinder with an attached splitter plate was investigated numerically. To see the effect of the splitter plate length and inclination angle on the pressure distributions and vortex shedding, numerical simulations were done for moderate Reynolds numbers ranging from 100 to 500 in two different splitter plate lengths (1 and 2 diameters), and the angles between splitter plate and wake centerline was changed from 0 to 45 deg. Results indicate that the wake structure and length are dependent on the inclination angle of splitter plate. Near wake length is almost unchanged when θ>25 deg. On the other hand, circular cylinder’s drag coefficient is distinctly affected by the position of vortex. And significant local peaks of the RMS lift coefficient are obtained at θ=15 deg and 5 deg for L=1D and 2D respectively. The lift force is in one direction when the inclination angle is over a critical value. In addition, the non-dimensional Strouhal number representing the vortex shedding frequency characteristics varies as a function of the angle and has peak values at θ=20 and 5 deg for L=1D and 2D respectively. And the longer splitter plate causes more decrease in the Strouhal number for θ>15 deg.

scholarly journals Flow structure from a horizontal cylinder coincident with a free surface in shallow water flow

2012 ◽  
Vol 16 (1) ◽  
pp. 93-107 ◽  
Author(s):  
Ali Kahraman ◽  
Muammer Özgören ◽  
Beşir Şahin
Keyword(s):  
Free Surface ◽  
Shallow Water ◽  
Water Flow ◽  
Vortex Formation ◽  
Flow Characteristics ◽  
Lower Surface ◽  
Horizontal Cylinder ◽  
Bottom Surface ◽  
Shallow Water Flow ◽  
Cylinder Diameter

Vortex formation from a horizontal cylinder coincident with a free surface of a shallow water flow having a depth of 25.4 [mm] was experimentally investigated using the PIV technique. Instantaneous and time-averaged flow patterns in the wake region of the cylinder were examined for three different cylinder diameter values under the fully developed turbulent boundary layer condition. Reynolds numbers were in the range of 1124? Re? 3374 and Froude numbers were in the range of 0.41 ? Fr ? 0.71 based on the cylinder diameter. It was found that a jet-like flow giving rise to increasing the flow entrainment between the core and wake regions depending on the cylinder diameter was formed between the lower surface of the cylinder and bottom surface of the channel. Vorticity intensity, Reynolds stress correlations and the primary recirculating bubble lengths were grown to higher values with increasing the cylinder diameter. On the other hand, in the case of the lowest level of the jet-like flow emanating from the beneath of the smallest cylinder, the variation of flow characteristics were attenuated significantly in a shorter distance. The variation of the reattachment location of the separated flow to the free-surface is a strong function of the cylinder diameter and the Froude number.

Dealing with shallow-water flow in the deepwater Gulf of Mexico

2002 ◽  
Vol 21 (7) ◽  
pp. 660-668 ◽  
Author(s):  
R. M. Ostermeier ◽  
J. H. Pelletier ◽  
C. D. Winker ◽  
J. W. Nicholson ◽  
F. H. Rambow ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Shallow Water ◽  
Water Flow ◽  
Shallow Water Flow
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