Onset of vortex shedding from a bluff body modified from square cylinder to normal flat plate

Rastan, M.R.; Alam, Md. Mahbub; Zhu, Hongjun; Ji, Chunning

doi:10.1016/j.oceaneng.2021.110393

Cited by 23 publications

(3 citation statements)

References 81 publications

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“…This shows that the change in AR has a significant effect on the flow mode transitions around sharp-edged bodies. These findings are also consistent with those of Rastan et al [38]. According to these authors, the critical Re for the onset of vortex shedding is lower in cases of vertical flat plates than in square cylinders.…”

Section: Regime IIIsupporting

confidence: 93%

“…This is because the unsteadiness in the flow starts much earlier and is more significant in the case of AR = 2:1, as discussed previously. Rastan et al [38] reported in their study that the average drag force decreases with Re for AR > 0.5, and an opposite trend occurs for AR < 0.5 in the range of Re = 40 to 100. In the present case, at AR = 1:2, the CDmean remains almost constant, while for AR = 2:1, it increases with Re in the range from 40 to 100.…”

Section: Force Statistics: Comparison Between Ar = 1:2 and 2:1mentioning

confidence: 89%

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Rectangular Cylinder Orientation and Aspect Ratio Impact on the Onset of Vortex Shedding

Tahir,

Abbasi,

Rahman

et al. 2023

Mathematics

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Rectangular cylinders have the potential to provide valuable insights into the behavior of fluids in a variety of real-world applications. Keeping this in mind, the current study compares the behavior of fluid flow around rectangular cylinders with an aspect ratio (AR) of 1:2 or 2:1 under the effect of the Reynolds number (Re). The incompressible lattice Boltzmann method is used for numerical computations. It is found that the flow characteristics are highly influenced by changes in the aspect ratio compared to the Reynolds number. The flow exhibits three different regimes: Regime I (steady flow), Regime II (initial steady flow that becomes unsteady afterward), and Regime III (completely unsteady flow). In the case of the cylinder with an aspect ratio of 2:1, vortex generation, variation in drag, and the lift coefficient occur much earlier at very low Reynolds numbers compared to the cylinder with an aspect ratio of 1:2. For the cylinder with an aspect ratio of 1:2, the Reynolds number ranges for Regimes I, II, and III are 1 ≤ Re ≤ 120, 121 ≤ Re ≤ 144, and 145 ≤ Re ≤ 200, respectively. For the cylinder with an aspect ratio of 2:1, the Reynolds number ranges for Regimes I, II, and III are 1 ≤ Re ≤ 24, 25 ≤ Re ≤ 39, and 40 ≤ Re ≤ 200, respectively. The cylinder with an aspect ratio of 1:2 is found to have the ability to stabilize the incoming flow due to its extended after-body flatness. Generally, it has been found that a cylinder with an AR of 2:1 is subjected to higher pressures, higher drag forces, higher curvatures of cross-flow rotations, and higher amplitudes of flow-induced drag, as well as higher lift coefficients and lower shedding frequencies, compared to cylinders with an AR of 1:2. In Regime III, elliptic and vertically mounted airfoil-like flow structures are also observed in the wake of the cylinders.

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Section: Regime IIIsupporting

confidence: 93%

Section: Force Statistics: Comparison Between Ar = 1:2 and 2:1mentioning

confidence: 89%

Rectangular Cylinder Orientation and Aspect Ratio Impact on the Onset of Vortex Shedding

Tahir,

Abbasi,

Rahman

et al. 2023

Mathematics

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“…(e.g. Alam 2014;Derakhshandeh & Alam 2019;Alam, Abdelhamid & Sohankar 2020;Rastan & Alam 2021;Chen et al 2022;Rastan et al 2022). Further surface modification of a slender cylinder (with either a circular, square or elliptic cross-section) into a sinusoidal waveform along the spanwise direction can significantly alter the near wake as well as fluid forces (e.g.…”

Section: Introductionmentioning

confidence: 99%

Wake of wavy elliptic cylinder at a low Reynolds number: wavelength effect

et al. 2023

Self Cite

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Effects of the spanwise wavelength (λ) of a sinusoidal wavy cylinder with elliptic cross-section on wake structures and fluid forces are numerically investigated at a Reynolds number Re = 100. A wide range of the wavelength, $0.43 \le \lambda /{D_m} \le 8.59$ , is considered with a wave amplitude of a/Dm = 0.048, where Dm is the hydraulic diameter of the wavy cylinder. Based on vortical structures, Strouhal number (St) and wake closure length (Lc), fluid forces, streamline topologies and spatio-temporal evolutions of the near wake, five distinct flow patterns (I–V) are identified depending on λ/Dm. The drag force reaches its minimum in pattern III, the fluctuating lift force is zero in flow patterns III and IV. Distinct from the classical flow where alternate vortex shedding occurs synchronously over the entire cylinder span, flow pattern IV has alternate vortex shedding over a one half-wavelength of the wavy elliptic cylinder, antiphased with that over the other half-wavelength, thus leading to zero fluctuating lift over one complete wavelength. A thorough comparison of the wakes is made between the wavy elliptic cylinder and wavy circular or square cylinder, distinguishing the underlying flow physics behind the salient behaviours observed.

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High speed flows with particles on demand: Boundary conditions

Bhadauria,

Karlin

2024

Computers & Fluids

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Onset of vortex shedding from a bluff body modified from square cylinder to normal flat plate

Cited by 23 publications

References 81 publications

Rectangular Cylinder Orientation and Aspect Ratio Impact on the Onset of Vortex Shedding

Rectangular Cylinder Orientation and Aspect Ratio Impact on the Onset of Vortex Shedding

Wake of wavy elliptic cylinder at a low Reynolds number: wavelength effect

High speed flows with particles on demand: Boundary conditions

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