Suppression of vortex shedding using a slit through the circular cylinder at low Reynolds number

Mishra, Alok; De, Ashoke

doi:10.1016/j.euromechflu.2021.06.009

Cited by 24 publications

(5 citation statements)

References 67 publications

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“…As I ≥ 2.5, the secondary vortices gradually became larger, and the main vortices were weakened by the jet. This phenomenon that the overall instability and vortex shedding can be suppressed through the jet was reflected in the research of Mishra et al The jet can even make the main vortex disappear at the appropriate jet strength [37].…”

Section: Physical Mechanisms Of Flow and Heat Transfermentioning

confidence: 92%

“…According to the above analysis, the instability of the wake vortices caused by the jet pointing backwards in the cylinder enhanced the heat transfer. Mishra et al found that the jet angle had an influence on the interaction between the primary vortex and the secondary vortex [37]. Therefore, the impacts of the jet angle on the mixing of wake vortices and heat transfer performance deserved investigation.…”

Section: Heat Transfer Performancementioning

confidence: 99%

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Enhancement of Heat Transfer in a Microchannel via Passive and Active Control of a Jet Issued from the Circular Cylinder

Xin¹,

Kong²,

Chen³

2022

Energies

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The heat transfer enhancement of a jet issued from the circular cylinder placed in a three-dimensional microchannel at low Reynolds numbers were studied systematically by using the numerical simulation. The effects of the jet on thermal efficiency were evaluated by varying injection ratios (I) and jet angles (θ). The physical mechanism of heat transfer was revealed through the analyses of vorticity dynamic and temperature field. The results showed that the thermal efficiency was proportional to the injection ratio at Re = 100 and 200. However, at Re = 300, the thermal efficiency did not increase monotonically with the injection ratio, and the local maximum value of heat transfer efficiency, slightly less than the highest thermal efficiency, appeared at I = 1.5. This was a result of the jet inducing the vortex generated on the cylinder to become unstable. Furthermore, the change of jet angle had a better effect on heat transfer performance compared to the increase in the injection ratio. The separation point of the flow over cylinder and the vortices in the near field were adjusted by the change in jet angle. At the appropriate range of the jet angle, the wake vortices in the near field transitioned from quasi-steady to unsteady in the far field. The instability of wake vortices can disturb the thermal boundary layer near the wall so as to improve the heat transfer performance.

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Section: Physical Mechanisms Of Flow and Heat Transfermentioning

confidence: 92%

Section: Heat Transfer Performancementioning

confidence: 99%

Enhancement of Heat Transfer in a Microchannel via Passive and Active Control of a Jet Issued from the Circular Cylinder

Xin¹,

Kong²,

Chen³

2022

Energies

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“…Olsen & Rajagopalan 12 also reported the increased strength of the vortices for the normal slit case. Recently, many studies [13][14][15][16][17][18] have looked at the effect of the slit placed parallel to the incoming flow and demonstrated the efficient VIV suppression. Ma and Kuo 19 showed that the pressure difference between the slit openings is the driving force for the periodic suction/blowing with zero-net-mass flux.…”

Section:  =mentioning

confidence: 99%

Dynamics of vortex-induced-vibrations of a slit-offset circular cylinder for energy harvesting at low Reynolds number

Verma

2022

Physics of Fluids

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Vortex-Induced Vibrations (VIV) offer a safe, renewable, and environmentally friendly energy source for energy harvesting. To enhance the energy harvesting capability of the circular cylinder-based devices, the authors explore the placement of the normal slit by determining the most effective slit offset location from the cylinder's center. A series of numerical simulations are conducted to determine the utility of the slit placement on the circular cylinder and how it influences (positively/negatively) the harvester's performance for a 1-degree-of-freedom (1-DOF) VIV system. The study shows that the slit-cylinder displays the three-branch VIV response (i.e. initial branch (IB), upper branch (UB), and lower branch (LB)). At a Reynolds number of 150, the cylinder with no slit exhibits the two-branch VIV response (i.e. IB and LB) but lacks the upper branch. The results indicate that adding a normal slit to the middle of the cylinder improves the alternating suction and blowing phenomena. Offsetting it from the center towards the back stagnation point suppresses the VIV and makes it unsuitable for energy harvesting applications. While positioning the slit toward the front stagnation point improves aerodynamic lift, and the cylinder sheds vortex closer to each other. It enhances the amplitude of transverse oscillation and, consequently, the power extraction. In addition, the peak energy transfer ratio for these scenarios is comparable to that of the no-slit case but with a larger range of peak energy transfer ratio values. It makes it suitable for energy harvesting applications.

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“…Another study [23] found that larger slits at higher Reynolds numbers increase drag and vortex shedding frequency. In another work, Mishra and De [24] examined the flow within the slit for Reynolds numbers varying between 100 and 500. They tested slits with S/D ≤ 0.25, and reported that for Re < 300, periodic vortex shedding occurs for all slit sizes, while for Re higher than 300, and S/D greater than 0.15 irregular vortex shedding appear in the wake.…”

Section: Introductionmentioning

confidence: 99%

Passive Vibration Reduction in Circular Cylinders: The Role of Slits

Ali,

Islam,

Janajreh

2024

Proceedings of the 9th World Congress on Momentum, Heat and Mass Transfer

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This work investigates a passive flow control method to mitigate vortex-induced vibration (VIV) by introducing a slit into a circular structure. The impact of varying slit sizes on the behaviour of a cylinder subjected to VIV is investigated across different reduced velocities (Ur) at a Reynolds number (Re) of 100. The size of the slit (S/D) is adjusted from 0 (without slit) to 0.1 & 0.2, where S corresponds to the width of slit & D the cylinder diameter. The mass and damping ratios are fixed at m* = 10 and ζ = 0.005, respectively, while Ur is varied from 2 to 10. The numerical analysis is conducted using Ansys/Fluent, incorporating mesh motion to consider cylinder vibration. The outcomes are presented in terms of vibration amplitude & frequency, drag & lift coefficients, Strouhal number, and vorticity contours. The findings suggest that the slit reduces lift and drag coefficients, effectively suppressing VIV. Examining maximum vibration amplitude, a 10% slit results in a 5.16% decrease, whereas a 20% slit leads to a substantial 34.27% reduction compared to a solid cylinder.

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Suppression of vortex shedding using a slit through the circular cylinder at low Reynolds number

Cited by 24 publications

References 67 publications

Enhancement of Heat Transfer in a Microchannel via Passive and Active Control of a Jet Issued from the Circular Cylinder

Enhancement of Heat Transfer in a Microchannel via Passive and Active Control of a Jet Issued from the Circular Cylinder

Dynamics of vortex-induced-vibrations of a slit-offset circular cylinder for energy harvesting at low Reynolds number

Passive Vibration Reduction in Circular Cylinders: The Role of Slits

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