Showing papers on "Vortex-induced vibration published in 2020"
TL;DR: In this article, the effects of the downstream plate length and the arrangement of plates on the hydrodynamic forces, vibration response and flow wake were examined using the direct numerical simulation (DNS).
102 citations
74 citations
TL;DR: In this paper, the VIV oscillation amplitudes and frequency lock-in ranges of a spring system-supported circular cylinder model are suppressed via passive-jet flow control in wind tunnel experiments.
50 citations
TL;DR: In this article, the authors proposed a self-tuning vortex-induced vibration (VIV)-based piezoelectric energy harvesting system with a slidable bluff body configured in a circular cylinder to improve the output energetic performance.
49 citations
TL;DR: In this article, the fluid-structure interaction (FSI) between the elastically supported cylinder-plate body and the surrounding flow is studied numerically and an FSI solution procedure is developed based on the characteristic-based split finite element method, and its accuracy and stability are validated using vortex-induced vibrations (VIVs) of a plain circular cylinder with benchmark solutions.
Abstract: Flow-induced vibration (FIV) of a circular cylinder with an attached splitter plate in a laminar flow with Re = 100 is studied numerically. First, the mechanical model along with mathematical formulations is proposed to describe the fluid-structure interaction (FSI) between the elastically supported cylinder–plate body and the surrounding flow. Subsequently, an FSI solution procedure is developed based on the characteristic-based split finite element method, and its accuracy and stability are validated using vortex-induced vibrations (VIVs) of a plain circular cylinder with benchmark solutions. Finally, using FSI simulations, effects of the plate length (L), reduced velocity, mass ratio and damping coefficient on the dynamic response, fluid load, and flow pattern of the cylinder–plate assembly are investigated in detail. As the plate length increases from L/D = 0–1.5 (D is the cylinder diameter), three FIV modes are observed successively: VIV, coupled VIV and galloping, and separated VIV and galloping, along with three vortex modes in the wake: 2S (two separated vortices in one cycle), P+S (a vortex pair and a separated vortex in one cycle), and 2P (two vortex pairs in one cycle). Moreover, it is found that the lift components generated from the splitter plate and the cylinder behave, respectively, as the driving force and the suppressing force of galloping, and the transition from VIV to galloping can be taken as a result of the competition between them. The cylinder–plate model presented could be taken as a benchmark model demonstrating the VIV-galloping interaction and applied to the design of novel FSI-based energy harvesters.
46 citations
TL;DR: In this article, a rotational nonlinear energy sink (RNES) was proposed to passively harnessing a substantial amount of kinetic energy from the rectilinear motion of the cylinder, leading to a significant suppression of cylinder oscillation and a nearly twofold reduction in drag.
Abstract: We computationally investigate flow past a three-dimensional linearly sprung cylinder undergoing vortex-induced vibration (VIV) transverse to the free stream and equipped with an internal dissipative rotational nonlinear energy sink (NES). The rotational NES consists of a line mass allowed to rotate at constant radius about the cylinder axis, with linearly damped rotational motion. We consider a value of the Reynolds number ($$\textit{Re}=10{,}000$$, based on the cylinder diameter and free-stream velocity) at which flow past a linearly sprung cylinder with no NES is three-dimensional and fully turbulent. For this $$\textit{Re}$$ value, we show that the rotational NES is capable of passively harnessing a substantial amount of kinetic energy from the rectilinear motion of the cylinder, leading to a significant suppression of cylinder oscillation and a nearly twofold reduction in drag. The results presented herein are of practical significance since they demonstrate a novel passive mechanism for VIV suppression and drag reduction in a high-$$\textit{Re}$$ bluff body flow, and lay down the groundwork for designing nonlinear energy sinks with a view to enhancing the performance of VIV-induced power generation in marine currents.
44 citations
TL;DR: A significant vortex-induced vibration was observed in a suspension bridge under a wind velocity of approximately 6 and 7 m/s, and with a maximum amplitude that exceeded the serviceability of the bridge.
Abstract: A significant vortex-induced vibration (VIV) was observed in a suspension bridge under a wind velocity of approximately 6 and 7 m/s, and with a maximum amplitude that exceeded the serviceability li...
36 citations
TL;DR: In this article, the mechanism of suppression for the vortex-induced vibration (VIV) of a free-vibrating circular cylinder by the helical wires is investigated using LES turbulence model.
35 citations
TL;DR: In this article, a new wake oscillator model with nonlinear coupling is proposed for the modelling of vortex-induced vibration, which is capable of reproducing both free and forced vibration experiments.
33 citations
TL;DR: In this article, the effect of FIV suppression of each cylinder on the response amplitude of other one, and the simultaneous vibration reduction of both cylinders are investigated based on fully-coupled fluid-structure interaction (FSI) simulations.
32 citations
TL;DR: In this paper, a spring-mounted circular cylinder in VIV was numerically investigated with 2D simulations to examine the effects of submergence depth on the energy conversion of the cylinder.
TL;DR: In this paper, the hydrodynamic coefficients of three equally spaced flexible cylinders subjected to FIV in an equilateral-triangular arrangement with a centre-to-centre spacing of 6 diameters were identified using an inverse analysis method according to the displacement response data obtained from model tests.
Abstract: Three equally spaced flexible cylinders are frequently applied in many engineering fields. The flow-induced vibration (FIV) hydrodynamic features of three such cylinders are not the same as those of an isolated single one and remain unknown. In this paper, the hydrodynamic coefficients for three flexible cylinders subjected to FIV in an equilateral-triangular arrangement with a centre-to-centre spacing of 6 diameters were identified using an inverse analysis method according to the displacement response data obtained from model tests. The lift coefficient, varying drag coefficient and added mass coefficient at the dominant frequency were calculated by decomposing the cross-flow (CF) and in-line (IL) fluctuating forces. Three typical cases of an equilateral-triangular configuration (A, B, and C), which correspond to flow incidence angles of 0 ∘ , 30 ∘ , and 60 ∘ , were studied and discussed (the incidence angle is defined as the angle between the flow orientation and the line linking the centre points of one cylinder and the equilateral-triangular configuration). The hydrodynamic coefficients of the upstream cylinders are insignificantly influenced by the downstream cylinders. In contrast, the wake of the upstream cylinders impose a notable effect on the IL hydrodynamic coefficients of the downstream cylinders. Two robust frequency components ( f v , I L and f v , I L _ 1 ∕ 2 ) were observed in the IL vibrations of the downstream cylinders. The IL hydrodynamic forces at f v , I L have similar features to the classical vortex shedding forces of an isolated flexible cylinder. However, the IL hydrodynamic forces at f v , I L _ 1 ∕ 2 exhibit distinct behaviours that are closely related to the unique response characteristics in the IL direction. In addition, the IL fluctuating force coefficients and varying drag coefficients at f v , I L _ 1 ∕ 2 are relatively small and change slowly with the reduced velocity.
TL;DR: In this paper, the effect of 2DOF flow-induced vibration on the characteristics of forced convective heat transfer from an isothermal circular cylinder is numerically simulated by commercial software-FLUENT in combination with the user defined function.
TL;DR: In this paper, the cross-flow vortex-induced vibration features of a submerged floating tunnel element, which is composed of two rigidly connected cylinders in a tandem configuration, were investigated via a self-oscillation model test in a steady flow.
TL;DR: In this article, the Navier-Stokes equations, the continuity and pressure Poisson equations written for an incompressible constant property Newtonian fluid coupled with the structural equation are solved using the finite difference method.
TL;DR: In this article, an in-house fluid-structure interaction (FSI) solver, based on a sharp-interface immersed boundary method, is employed to solve the flow and thermal fields.
Abstract: Flow-induced vibration (FIV) of a D-section cylinder is computationally studied and utilized to augment convective heat transfer in a heated laminar channel flow. An in-house fluid–structure interaction (FSI) solver, based on a sharp-interface immersed boundary method, is employed to solve the flow and thermal fields. In conjunction, a spring–mass system is utilized to solve for the rigid structural dynamics. Using numerical simulations, we highlight that the oscillations of a D-section cylinder are driven by vortex-induced vibration and galloping. It is observed that as the cylinder vibrates, vortices are shed from the apex of the cylinder due to the separating shear layers. These vortices, categorized using shedding patterns, interact with the heated channel walls. This interaction results in disruption of the thermal boundary layer (TBL), thus leading to heat transfer augmentation. The enhancement in thermal performance has been quantified using time and space-averaged Nusselt numbers at the channel walls. It is observed that the oscillation amplitude of the D-section cylinder and the extent of vortex–TBL interaction are crucial for determining heat transfer augmentation. Both symmetric and asymmetric thermal augmentation at the top and bottom channel walls have been reported. Finally, to assess the effectiveness of heat transfer augmentation, the D-section cylinder FIV is compared to other FSI systems operating under similar conditions.
TL;DR: In this article, a Hilbert Transform-based approach is proposed to determine amplitude-dependent aerodynamic damping and other response characters associated with vertical and torsional vortex-induced vibrations (VIVs) and coupled flutter of bridges.
TL;DR: In this article, the effects of spatially staggered arrangements on the flow-induced vibration (FIV) characteristics of two identical flexible cylinders were experimentally studied in a towing tank.
TL;DR: In this paper, a model reduction approach based on the eigensystem realization algorithm is used to construct a reduced-order model in a state-space format, and the stability analysis of the coupled system is found to be dominant in the phenomenon of self-sustained VIV.
Abstract: In this paper, we present a stability analysis of passive suppression devices for the vortex-induced vibration (VIV) in the laminar flow condition. A data-driven model reduction approach based on the eigensystem realization algorithm is used to construct a reduced-order model in a state-space format. From the stability analysis of the coupled system, two modes are found to be dominant in the phenomenon of self-sustained VIV: namely, the wake mode, with frequency close to that of the wake flow behind a stationary cylinder; and the structure mode, with frequency close to the natural frequency of the elastically mounted cylinder. The present study illustrates that VIV can be suppressed by altering the structure mode via shifting of the eigenvalues from the unstable to the stable region. This finding is realized through the simulations of passive control devices, such as fairings and connected-C devices, wherein the presence of appendages breaks the self-sustenance of the wake–body interaction cycle. A detailed proper orthogonal decomposition analysis is employed to quantify the effect of a fairing on the complex interaction between the wake features. From the assessment of the stability characteristics of appendages, the behaviour of a connected-C device is found to be similar to that of a fairing, and the trajectories of the eigenspectrum are nearly identical, while the eigenspectrum of the cylinder–splitter arrangement indicates a galloping behaviour at higher reduced velocities. Finally, we introduce a stability function to characterize the influence of geometric parameters on VIV suppression.
TL;DR: In this paper, a vortex-induced vibration of a circular cylinder near a plane boundary has been investigated experimentally for 2,500 ≤ R e D ≤ 10,000, 3.0 ≤ U * ≤ 12.0, 0.3 ≤ S * ≤ 8, and m * = 5.3, where R eD is the Reynolds number based on cylinder diameter, U * is reduced velocity, S * is the gap distance between the planar wall and the cylinder, and m* is the system's mass ratio.
TL;DR: In this article, the authors developed a novel algorithm for flow pattern classification using the vibration signal from a vertical pipe conveying a liquid-gas two-phase flow to determine the flow pattern.
TL;DR: In this article, two plasma actuators were disposed symmetrically on the surface of the cylinder along the span that transferred momentum to the fluid by means of a dielectric barrier discharge.
TL;DR: In this article, numerical simulations of two-degree-of-freedom flow-induced vibration of three elastically mounted tandem cylinders are performed for a low Reynolds number of Re ǫ = 150.
TL;DR: In this paper, a model based on the vector form intrinsic finite element (VFIFE) method is proposed to study vortex-induced vibration (VIV) problems of top-tensioned risers, which is applicable to the fully-coupled cross-flow and in-line riser VIV scenarios.
TL;DR: In this article, the authors examined the viability of energy harvesting by three rigidly coupled cylinders in an equilateral triangular pattern, as well as reveal the flow-induced vibration responses of such a system.
TL;DR: In this article, the VIV responses of bluff bodies with different rear edges (semicircle (T1), triangular (T2), trapezoidal (T3) and rectangular (T4)) were numerically investigated using Computational Fluid Dynamics (CFD) methods for Reynolds number range of 8.0 × 103.
22 May 2020
TL;DR: In this paper, an implicit partitioned approach is utilized to couple a sharp-interface immersed boundary method-based flow solver and a finite-element method based structural solver.
Abstract: We present the development and benchmarking of an in-house fluid–structure interaction (FSI) solver. An implicit partitioned approach is utilized to couple a sharp-interface immersed boundary method-based flow solver and a finite-element method-based structural solver. In the present work, the coupling is accelerated using a dynamic under-relaxation scheme. The revised coupling is around two to three times faster and numerically stable, as compared to the one that uses a constant under-relaxation parameter. The solver is validated against two FSI benchmarks in which a thin, finite thickness, elastic splitter plate is attached to the lee side of a circular or square rigid cylinder, subjected to laminar flow. In these two-dimensional benchmarks, the flow induces a wave-like deformation in the plate, and it attains a periodic self-sustained oscillation. We employ the FSI solver to analyze the flow-induced vibration (FIV) of the plate in a uniform laminar free-stream flow for a wide range of mass ratio and bending stiffness at Reynolds number (Re) of 100, based on the diameter of the cylinder. At the given Re, two-dimensional numerical simulations show that the FIV of the plate effectively depends only on the mass ratio and bending stiffness. The largest displacement of the plate vibration is found to occur in the lock-in region, where the vortex shedding frequency of the coupled fluid–structure system is close to the natural frequency of the splitter plate. We briefly discuss wake structures and phase plots for different cases of mass ratio and bending stiffness.
TL;DR: Based on the flow pattern and vortex structure around the section simulated by computational fluid dynamics, Wang et al. as discussed by the authors inferred that the aerodynamic interactions of the large-scale vortices under the deck and the shedding Vortices in the wake zone periodically change the fluctuating pressures on the section and induce the vibrations of the deck.
TL;DR: In this article, the flow-induced vibration (FIV) of flexible multi-cylinders in tandem, side-by-side and staggered arrangements were conducted in an atmospheric boundary layer wind tunnel over a wide spacing ratio and incidence angles.
TL;DR: In this article, the authors investigated the dynamics of vortex-induced vibration of an elastically mounted cylinder with very low values of mass and damping, and they used two methods to investigate this canonical problem: first they calculate the instantaneous phase between the cylinder motion and the fluid forcing; second they decompose the total hydrodynamic force into drag and lift components that act along and normal to the instantaneous effective angle of attack.