On the origin of wake-induced vibration in two tandem circular cylinders at low Reynolds number

Mysa, Ravi Chaithanya; Kaboudian, Abouzar; Jaiman, Rajeev K.

doi:10.1016/j.jfluidstructs.2015.11.004

Cited by 87 publications

(17 citation statements)

References 31 publications

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“…The temporal discretizations of both the fluid and structural equations are formulated in the variational generalized-α framework and the systems of linear equations are solved via the Generalized Minimal Residual (GMRES) solver (Jaiman et al 2015(Jaiman et al , 2016b. The validation results of the two-and three-dimensional simulations are reported in Liu & Jaiman (2016), Mysa et al (2016) and Li et al (2016). These validation results and convergence investigations provide the validity and reliability of the fluid-structure solver to simulate the gap flow and VIV interaction.…”

Section: Numerical Methodologymentioning

confidence: 97%

Dynamics and stability of gap-flow interference in a vibrating side-by-side arrangement of two circular cylinders

Liu

Jaiman

2018

J. Fluid Mech.

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In this work, the coupled dynamics of the gap flow and the vortex-induced vibration (VIV) on a side-by-side (SBS) arrangement of two circular cylinders is numerically investigated at moderate Reynolds number 100Re 800. The influence of VIV is incorporated by allowing one of the cylinders to freely vibrate in the transverse direction, which is termed as a vibrating side-by-side (VSBS) arrangement. A comparative analysis is performed between the stationary side-by-side (SSBS) and the VSBS arrangements to investigate the characteristics of the complex coupling between the VIV and the gap flow in a three-dimensional flow. The results are also contrasted against the isolated stationary and the vibrating configurations without any proximity and gap flow interference. Of particular interest is to establish a relationship between the VIV, the gap flow and the near-wake instability behind bluff bodies. We find that the kinematics of the VIV regulates the streamwise vorticity concentration, which accompanies with a recovery of two-dimensional hydrodynamic responses at the peak lock-in stage. On the other hand, the near-wake instability may develop around an in-determinant two-dimensional streamline saddle point along the interfaces of a pair of imbalanced counter-signed vorticity clusters. The vorticity concentration difference of adjacent vorticity clusters and the fluid momentum are closely interlinked with the prominence of streamwise vortical structures. In both SSBS and VSBS arrangements, the flip-flopping frequency is significantly low for the three-dimensional flow, except at the VIV lock-in stage for the VSBS arrangement. A quasi-stable deflected gap flow regime with negligible spanwise hydrodynamic (i.e., two-dimensional) response is found at the peak lock-in stage of VSBS arrangements. Owing to the gap-flow proximity interference, a high streamwise vorticity concentration is observed in its narrow near-wake region. The increase of the gap-flow proximity interference tends to stabilize the VIV lock-in, which eventually amplifies the spanwise correlation length and weakens the streamwise vortical structures. We employ the dynamic mode decomposition procedure to characterize the space-time evolution of the primary vortex wake.

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Section: Numerical Methodologymentioning

confidence: 97%

Dynamics and stability of gap-flow interference in a vibrating side-by-side arrangement of two circular cylinders

Liu

Jaiman

2018

J. Fluid Mech.

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“…The exorbitant computational costs for modeling physical systems are not specific to the field of cardiac dynamics. For example, fluid flow around or between obstacles is a common phenomenon in applications that range from offshore oil and gas risers ( 19 ), wind turbines ( 20 ), airplanes, civil structures, and cooling towers in thermal power plants ( 21 ) to small-scale problems such as blood flow in vessels, flow in porous media, and many more. In external flows, vortex shedding subjects structures to cyclic loading that, in turn, can lead to fatigue problems in the structures.…”

Section: Modelsmentioning

confidence: 99%

Real-time interactive simulations of large-scale systems on personal computers and cell phones: Toward patient-specific heart modeling and other applications

2019

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Cardiac dynamics modeling has been useful for studying and treating arrhythmias. However, it is a multiscale problem requiring the solution of billions of differential equations describing the complex electrophysiology of interconnected cells. Therefore, large-scale cardiac modeling has been limited to groups with access to supercomputers and clusters. Many areas of computational science face similar problems where computational costs are too high for personal computers so that supercomputers or clusters currently are necessary. Here, we introduce a new approach that makes high-performance simulation of cardiac dynamics and other large-scale systems like fluid flow and crystal growth accessible to virtually anyone with a modest computer. For cardiac dynamics, this approach will allow not only scientists and students but also physicians to use physiologically accurate modeling and simulation tools that are interactive in real time, thereby making diagnostics, research, and education available to a broader audience and pushing the boundaries of cardiac science.

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“…size of the cylinder. Mysa et al [27] studied the VIV of the two tandem cylinders. It was found that the maximum amplitude of the downstream cylinder of the two tandem cylinders was significantly larger than that of the single cylinder, and the critical buckling deceleration was between 5.0 and 6.0 at different spacing ratios.…”

Section: Introductionmentioning

confidence: 99%

Effect of Gap Flow on the Characteristics of Flow-Around and Flow-Induced Vibration for Two Circular Cylinders with Roughness Strips

Yang

Ding

et al. 2019

Applied Sciences

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In order to understand the gap flow between two cylinders, the characteristics of flow around two stationary cylinders and the flow-induced vibration of two staggered cylinders with roughness strips are numerically studied. The lift-drag responses, Strouhal number (St) and wake structure of two stationary cylinders in tandem, as well as the vibration response and vortex pattern of two oscillating staggered cylinders are analyzed. The results indicate that the spacing d c of two stationary cylinders at which the gap flow can be observed is different for different Re, and d c is 3D when Re = 2000 and d c = 2.5D at Re = 6000~14,000. When the distance d = d c , the force coefficient and St of two cylinders increase sharply. For the two oscillating staggered cylinders, there is a critical reduced velocity U c * = 7, which makes the amplitude magnitude relationship of the two cylinders change. With the change of the reduced velocity, the vibration frequencies of the two cylinders are consistent. When the staggered distance increases, the frequency difference of the two cylinders decreases. At the same inflow velocity, with the increase of staggered distance, a gap flow is formed between the two cylinders. When T > 0.6D and U* < 8, the gap flow becomes the main factor affecting the vibration of the two cylinders, which can be divided into the dominant region of gap flow.The FIV of a bluff body is a very complicated fluid-solid coupling process. Many studies have been done in this field, mainly focusing on the FIV characteristics and vibration control of the bluff body. The representative reviews of FIV of cylinders are by Williamson [5] and Bearman [6]. The control of FIV is embodied in two aspects. On the one hand, it is the suppression of vibration. Canpolat [7] found that rectangular grooves on a cylinder can effectively control flow through PIV experiments. Feng [8] used a water tunnel experimentation study and found that a synthetic jet can significantly change the scale of eddy current and wake mode. Lam [9] discussed the flow around a corrugated cylinder by large eddy simulation and experiment, and they controlled the vibration of the tube bundle in a heat exchanger by adding a corrugated cylinder to the tube bundle array. Zhu [10] and Song [11] studied the inhibition effect of small control rods on vortex-induced vibration (VIV). The former compared the VIV characteristics under different rod numbers, diameter ratios and gap ratios. It was found that when the attachment had nine control rods, the diameter ratio was 0.15, and the clearance ratio was 0.6, the inhibition effect of VIV was the best. The latter simulated the VIV characteristics of a cylinder with three small control rods at different angles of attack and clearance ratios. It was found that the inhibition effect was the best when the angle of attack was 45 and the clearance ratio was 0.9. Wu et al. [12] found a new method to control VIV: A twisted cylinder, which was applied to a semi-submersible offshore platform. Compared with a square cylinder, the...

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On the origin of wake-induced vibration in two tandem circular cylinders at low Reynolds number

Cited by 87 publications

References 31 publications

Dynamics and stability of gap-flow interference in a vibrating side-by-side arrangement of two circular cylinders

Dynamics and stability of gap-flow interference in a vibrating side-by-side arrangement of two circular cylinders

Real-time interactive simulations of large-scale systems on personal computers and cell phones: Toward patient-specific heart modeling and other applications

Effect of Gap Flow on the Characteristics of Flow-Around and Flow-Induced Vibration for Two Circular Cylinders with Roughness Strips

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