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

Akıllı, Hüseyin; Karakuş, Cuma; Akar, Atakan; Şahi̇n, Beşi̇r; Tumen, N. Filiz

doi:10.1115/1.2903813

Cited by 71 publications

(25 citation statements)

References 27 publications

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“…8(e), (f), and (g). The elongation of the wake region is an indication of the substantial attenuation of vortex formation (Akilli et al, 2008). At L/D = 4.5, the vortex shedding is θs ∆θ s θs θ a -= Figure 9 presents the variation of root mean squared value of the lift force coefficient, C L , with respect to L/D depending on the Reynolds numbers.…”

Section: Shedding Frequency (Strouhal Number)mentioning

confidence: 98%

“…A splitter plate was attached to the cylinder and placed along the center of the wake. Akilli et al (2008) conducted the laboratory experiments with the splitter thicknesses of 0.016D, 0.04D, and 0.08D. They noted that the plate thickness has no considerable effect on the flow structure.…”

Section: Computational Domain and Boundary Conditionsmentioning

confidence: 99%

“…In a certain case, they achieved 38.6% reduction of the drag coefficient. In addition, splitter plate is known as a passive method and one of the most successful mean to control the vortex and so has been studied in the several works (e.g., Roshko, 1955;Akilli et al, 2008;Gerrard, 1966). Roshko (1955) used a splitter plate to observe the change of flow at 1.45×10 4 of the Reynolds number, Re, with respect to the ratio between the length of splitter, L, and the diameter of cylinder, D. He found that a splitter plate of L = 5D reduced the vortex shedding and pressure drag on the cylinder by 63% compared to the one without the splitter.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of flow around circular cylinder with splitter plate

Ahn

Hwang

2015

KSCE J Civ Eng

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The flow around a single circular cylinder with splitter plate was investigated using Computational Fluid Dynamics. The present study investigated the effects of varying splitter plate length and the Reynolds numbers on flow characteristic, such as vortex shedding, drag force, lift force, separation point, pressure, and friction coefficients of the cylinder. It was revealed that the vortex shedding behind cylinder is completely suppressed when the splitter plate length is longer than the critical value, which is proportional to the Reynolds number. The variation of drag and lift coefficients with respect to splitter length can be classified into two patterns of a monotonic decrease and a general decrease but with small increase. We found that the first pattern occurs at Reynolds number ≤ 180 and higher Reynolds number gives the second pattern. When the splitter plate length is similar to the diameter of the cylinder, the vortex frequency, drag, and lift coefficients reach local minimum depending on the Reynolds number. A functional relationship between drag coefficient, length of splitter plate, and Reynolds number was determined.

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Section: Shedding Frequency (Strouhal Number)mentioning

confidence: 98%

Section: Computational Domain and Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of flow around circular cylinder with splitter plate

Ahn

Hwang

2015

KSCE J Civ Eng

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“…Therefore, many studies have been carried out in the past [1,2,3,5,6,7,9,10,12,13,14,16] to establish a method to control the vortex shedding which can be observed easily when fluid flows over a bluff body. A classification may be done by dividing the control methods into two categories, namely passive and active flow control.…”

Section: Introductionmentioning

confidence: 99%

Effect of High Porosity Screen on the Near Wake of a Circular Cylinder

Ozkan

Akıllı

Şahi̇n

2013

EPJ Web of Conferences

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Abstract. The change in flow characteristics downstream of a circular cylinder (inner cylinder) surrounded by a permeable cylinder (outer cylinder) made of a high porosity screen was investigated in shallow water using Particle Image Velocimetry (PIV) technique. The diameter of the inner cylinder, outer cylinder and the water height were kept constant during the experiments as d = 50 mm, D = 100 mm and h w = 50 mm, respectively. The depth-averaged free stream velocity was also kept constant as U = 180 mm/s which corresponded to a Reynolds number of Re d = 9000 based on the inner cylinder diameter. It was shown that the outer permeable cylinder had a substantial effect on the vortex formation and consequent vortex shedding downstream of the circular cylinder, especially in the near wake. The time averaged vorticity layers, streamlines and velocity vector field depict that the location of the interaction of vortices considerably changed by the presence of the outer cylinder. Turbulent statistics clearly demonstrated that in comparison to the natural cylinder, turbulent kinetic energy and Reynolds stresses decreased remarkably downstream of the inner cylinder. Moreover, spectra of streamwise velocity fluctuations showed that the vortex shedding frequency significantly reduced compared to the natural cylinder case.

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“…Hwang et al [3] investigated numerically the optimal location of the plate for maximum reduction. Akilli et al [4] performed experiments to study effect of the splitter plate length on the flow characteristics. Thombi et al [5] studied experimentally and numerically the flow control on a circular cylinder at transonic speed by inserting tabs inside the separated region.…”

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confidence: 99%

Large-eddy simulation of the compressible flow past a tabbed cylinder

Zhao

Sun

2012

Chin. Sci. Bull.

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The compressible flow past a tabbed cylinder has been studied numerically using large-eddy simulation for a free-stream Mach number M∞=0.75 and a Reynolds number based on the diameter Re=2×10 5 . Because of the passive control of the flow past a tabbed cylinder, the mean drag coefficient of tabbed cylinder is less than that of a corresponding circular cylinder with a drag reduction up to 33%. The fluctuating lift coefficient is greatly suppressed to be nearly zero. Drag reduction due to the shearing process prevails over that due to the compressing process in this flow. Through investigating the mechanisms relevant to passive control of the tab, it is found that suppression of the shear layer instability can lead to a higher-base-pressure distribution, which can reasonably be associated with drag reduction and suppression of the lift fluctuations. The analysis of convective Mach number and self-sustained oscillations phenomenon inside the shear layers indicates that both the compressible effect and high-frequency forcing result in suppression of the shear layer instability of tabbed cylinder. circular cylinder, shock wave, compressible turbulence, large-eddy simulation Citation:Xu C Y, Zhao L Q, Sun J H. Large-eddy simulation of the compressible flow past a tabbed cylinder.

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

Cited by 71 publications

References 27 publications

Numerical investigation of flow around circular cylinder with splitter plate

Numerical investigation of flow around circular cylinder with splitter plate

Effect of High Porosity Screen on the Near Wake of a Circular Cylinder

Large-eddy simulation of the compressible flow past a tabbed cylinder

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