Steady forces on a cylinder with oblique vortex shedding

Mittal, Sanjay; GS, Sidharth,

doi:10.1016/j.jfluidstructs.2013.11.009

Cited by 12 publications

(11 citation statements)

References 24 publications

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“…The significant reduction in the unsteadiness in the aerodynamic coefficients when the vortex shedding is oblique is very noticeable in the figure. This was explored in detail by Mittal and Sidharth (2014). Similar observations, via experiments, were also made by Williamson (1989).…”

Section: Problem Set-up and Computational Methodssupporting

confidence: 57%

“…It has been a subject of several earlier studies (for example, Zhao and Cheng, 2014;Sumner et al, 2004). Mittal and Sidharth (2014) investigated the flow past a cylinder at Re ¼ 100. They showed via linear stability analysis that there exist a vast number of unstable eigenmodes for the Re ¼ 100 flow past a cylinder, each corresponding to a certain angle of oblique vortices.…”

mentioning

confidence: 99%

“…The no-slip condition on the velocity on the side wall is known to induce oblique vortex shedding in the flow past a cylinder (Berger and Wille, 1972;Tritton, 1971;Gerich and Eckelmann, 1982;Williamson, 1989). Mittal and Sidharth (2014) showed that oblique shedding past a stationary cylinder is associated with spanwise periodicity. As a result, unlike in the parallel shedding, the fluid force on a segment of the cylinder consisting of an integral number of spanwise wavelengths of the oblique waves does not vary with time.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Vibrations of a cylinder in a uniform flow in the presence of a no-slip side-wall

Navrose¹,

Mittal²

2015

Journal of Fluids and Structures

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Section: Problem Set-up and Computational Methodssupporting

confidence: 57%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Vibrations of a cylinder in a uniform flow in the presence of a no-slip side-wall

Navrose¹,

Mittal²

2015

Journal of Fluids and Structures

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“…The occurrence of VIV and the possible application of the IP in this case still need to be elucidated. Previous studies concerning rigid cylinders indicate that the fluid loading caused by the slanted vortex formation in the case of oblique shedding would not lead to excitation of the body, owing to the alternating sign of the fluctuating forces along the span [35,42]. For a flexible body at a large inclination angle, the question arises whether such oblique shedding may induce vibrations (i.e.…”

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confidence: 99%

Vortex-induced vibrations of a flexible cylinder at large inclination angle

Bourguet

Triantafyllou

2015

Phil. Trans. R. Soc. A.

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The free vibrations of a flexible circular cylinder inclined at 80° within a uniform current are investigated by means of direct numerical simulation, at Reynolds number 500 based on the body diameter and inflow velocity. In spite of the large inclination angle, the cylinder exhibits regular in-line and cross-flow vibrations excited by the flow through the lock-in mechanism, i.e. synchronization of body motion and vortex formation. A profound reconfiguration of the wake is observed compared with the stationary body case. The vortex-induced vibrations are found to occur under parallel, but also oblique vortex shedding where the spanwise wavenumbers of the wake and structural response coincide. The shedding angle and frequency increase with the spanwise wavenumber. The cylinder vibrations and fluid forces present a persistent spanwise asymmetry which relates to the asymmetry of the local current relative to the body axis, owing to its in-line bending. In particular, the asymmetrical trend of flow–body energy transfer results in a monotonic orientation of the structural waves. Clockwise and counter-clockwise figure eight orbits of the body alternate along the span, but the latter are found to be more favourable to structure excitation. Additional simulations at normal incidence highlight a dramatic deviation from the independence principle, which states that the system behaviour is essentially driven by the normal component of the inflow velocity.

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“…When a fluid flows past a cylinder, two symmetric vortices with opposing rotations are formed that increase with increasing Reynolds number of the fluid. These vortices cause a fluctuation of pressure on either side of the cylinder, resulting in vibrations perpendicular to that of the fluid flow, which grows with the Reynolds number (Mittal and Sidharth 2014). The frequency of these vortex sheddinginduced vibrations is based on the nondimensional Strouhal number, which is defined in eq 2:…”

Section: Introductionmentioning

confidence: 99%

Performance evaluation of novel wet vibrational precipitator

Ali

Hedrick

Lutfullaeva

et al. 2019

Journal of the Air & Waste Management Association

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This study reports the development, construction, and initial testing of a novel vibrational precipitator (VP), patented at Ohio University in 2016, that uses vibrating metal cables with water running over them to capture particulate matter in an exhaust stream. Unlike traditional electrostatic precipitators relying on electric energy to capture particles, this new system uses the concept of vortex shedding to produce vibrations in vertical cables running perpendicular to an exhaust stream. Collisions between particles in the exhaust stream and these vibrating cables cause the particles to land onto a thin film of flowing water around the cables, which carries the particles downward for collection and removal. Initial tests with air containing particulates of 3 micron average particle size show capture efficiencies up to 54% using U.S. Environmental Protection Agency (EPA) Method 5 to measure the particulate concentrations at the upstream and downstream of a VP comprising 8 cells. These results show that this system, without consuming any electric energy, has a significant potential to be a simple and cost-effective way to treat particle-laden exhaust gases. Implications: In this work, for the first time, a novel precipitator is investigated that captures particles without using any particle charging and (hence) any electricity. The capture mechanism is governed by vibrations of collection electrodes, which are vertical steel cables wetted through continuous flow of water. Without any discharge electrodes, electrode suspension mechanism, and ability of the system to be installed in existing ducts, the novel precipitator becomes a simple chamber housing containing multiple collection electrode cells. The preliminary results show that this new technology can achieve net particulate matter capture efficiency of 54%. This paves a pathway forward for reducing capital and operating cost of air pollution control systems.

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Steady forces on a cylinder with oblique vortex shedding

Cited by 12 publications

References 24 publications

Vibrations of a cylinder in a uniform flow in the presence of a no-slip side-wall

Vibrations of a cylinder in a uniform flow in the presence of a no-slip side-wall

Vortex-induced vibrations of a flexible cylinder at large inclination angle

Performance evaluation of novel wet vibrational precipitator

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