Academic literature on the topic 'Wake Induced Vibration (WIV)'
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Journal articles on the topic "Wake Induced Vibration (WIV)"
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ASSI, G. R. S., P. W. BEARMAN, and J. R. MENEGHINI. "On the wake-induced vibration of tandem circular cylinders: the vortex interaction excitation mechanism." Journal of Fluid Mechanics 661 (August 16, 2010): 365–401. http://dx.doi.org/10.1017/s0022112010003095.
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The mechanism of wake-induced vibrations (WIV) of a pair of cylinders in a tandem arrangement is investigated by experiments. A typical WIV response is characterized by a build-up of amplitude persisting to high reduced velocities; this is different from a typical vortex-induced vibration (VIV) response, which occurs in a limited resonance range. We suggest that WIV of the downstream cylinder is excited by the unsteady vortex–structure interactions between the body and the upstream wake. Coherent vortices interfering with the downstream cylinder induce fluctuations in the fluid force that are not synchronized with the motion. A favourable phase lag between the displacement and the fluid force guarantees that a positive energy transfer from the flow to the structure sustains the oscillations. If the unsteady vortices are removed from the wake of the upstream body then WIV will not be excited. An experiment performed in a steady shear flow turned out to be central to the understanding of the origin of the fluid forces acting on the downstream cylinder.
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Zhang, Min, and Junlei Wang. "Experimental Study on Piezoelectric Energy Harvesting from Vortex-Induced Vibrations and Wake-Induced Vibrations." Journal of Sensors 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/2673292.
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A rigid circular cylinder with two piezoelectric beams attached on has been tested through vortex-induced vibrations (VIV) and wake-induced vibrations (WIV) by installing a big cylinder fixed upstream, in order to study the influence of the different flow-induced vibrations (FIV) types. The VIV test shows that the output voltage increases with the increases of load resistance; an optimal load resistance exists for the maximum output power. The WIV test shows that the vibration of the small cylinder is controlled by the vortex frequency of the large one. There is an optimal gap of the cylinders that can obtain the maximum output voltage and power. For a same energy harvesting device, WIV has higher power generation capacity; then the piezoelectric output characteristics can be effectively improved.
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Assi, G. R. S., P. W. Bearman, B. S. Carmo, J. R. Meneghini, S. J. Sherwin, and R. H. J. Willden. "The role of wake stiffness on the wake-induced vibration of the downstream cylinder of a tandem pair." Journal of Fluid Mechanics 718 (February 8, 2013): 210–45. http://dx.doi.org/10.1017/jfm.2012.606.
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AbstractWhen a pair of tandem cylinders is immersed in a flow the downstream cylinder can be excited into wake-induced vibrations (WIV) due to the interaction with vortices coming from the upstream cylinder. Assi, Bearman & Meneghini (J. Fluid Mech., vol. 661, 2010, pp. 365–401) concluded that the WIV excitation mechanism has its origin in the unsteady vortex–structure interaction encountered by the cylinder as it oscillates across the wake. In the present paper we investigate how the cylinder responds to that excitation, characterising the amplitude and frequency of response and its dependency on other parameters of the system. We introduce the concept of wake stiffness, a fluid dynamic effect that can be associated, to a first approximation, with a linear spring with stiffness proportional to $\mathit{Re}$ and to the steady lift force occurring for staggered cylinders. By a series of experiments with a cylinder mounted on a base without springs we verify that such wake stiffness is not only strong enough to sustain oscillatory motion, but can also dominate over the structural stiffness of the system. We conclude that while unsteady vortex–structure interactions provide the energy input to sustain the vibrations, it is the wake stiffness phenomenon that defines the character of the WIV response.
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Zhao, Enjin, Xiaoyu Xia, Fengyuan Jiang, Haiwen Tu, and Lin Mu. "Effect of porous media on wake-induced vibration (WIV) in tandem circular cylinder." Ocean Engineering 249 (April 2022): 110900. http://dx.doi.org/10.1016/j.oceaneng.2022.110900.
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Cao, Dongxing, Junru Wang, Xiangying Guo, S. K. Lai, and Yongjun Shen. "Recent advancement of flow-induced piezoelectric vibration energy harvesting techniques: principles, structures, and nonlinear designs." Applied Mathematics and Mechanics 43, no. 7 (July 2022): 959–78. http://dx.doi.org/10.1007/s10483-022-2867-7.
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AbstractEnergy harvesting induced from flowing fluids (e.g., air and water flows) is a well-known process, which can be regarded as a sustainable and renewable energy source. In addition to traditional high-efficiency devices (e.g., turbines and watermills), the micro-power extracting technologies based on the flow-induced vibration (FIV) effect have sparked great concerns by virtue of their prospective applications as a self-power source for the microelectronic devices in recent years. This article aims to conduct a comprehensive review for the FIV working principle and their potential applications for energy harvesting. First, various classifications of the FIV effect for energy harvesting are briefly introduced, such as vortex-induced vibration (VIV), galloping, flutter, and wake-induced vibration (WIV). Next, the development of FIV energy harvesting techniques is reviewed to discuss the research works in the past three years. The application of hybrid FIV energy harvesting techniques that can enhance the harvesting performance is also presented. Furthermore, the nonlinear designs of FIV-based energy harvesters are reported in this study, e.g., multi-stability and limit-cycle oscillation (LCO) phenomena. Moreover, advanced FIV-based energy harvesting studies for fluid engineering applications are briefly mentioned. Finally, conclusions and future outlook are summarized.
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Garg, Hemanshul, Atul Kumar Soti, and Rajneesh Bhardwaj. "Thermal buoyancy induced suppression of wake-induced vibration." International Communications in Heat and Mass Transfer 118 (November 2020): 104790. http://dx.doi.org/10.1016/j.icheatmasstransfer.2020.104790.
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Zhao, Daoli, Jie Zhou, Ting Tan, Zhimiao Yan, Weipeng Sun, Junlian Yin, and Wenming Zhang. "Hydrokinetic piezoelectric energy harvesting by wake induced vibration." Energy 220 (April 2021): 119722. http://dx.doi.org/10.1016/j.energy.2020.119722.
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Lee, H., K. Hourigan, and M. C. Thompson. "Vortex-induced vibration of a neutrally buoyant tethered sphere." Journal of Fluid Mechanics 719 (February 19, 2013): 97–128. http://dx.doi.org/10.1017/jfm.2012.634.
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AbstractA combined numerical and experimental study examining vortex-induced vibration (VIV) of a neutrally buoyant tethered sphere has been undertaken. The study covered the Reynolds-number range $50\leq \mathit{Re}\lesssim 12\hspace{0.167em} 000$, with the numerical ($50\leq \mathit{Re}\leq 800$) and experimental ($370\leqslant \mathit{Re}\lesssim 12\hspace{0.167em} 000$) ranges overlapping. Neutral buoyancy was chosen to eliminate one parameter, i.e. the influence of gravity, on the VIV behaviour, although, of course, the effect of added mass remains. The tether length was also chosen to be sufficiently long so that, to a good approximation, the sphere was constrained to move within a plane. Seven broad but relatively distinct sphere oscillation and wake states could be distinguished. For regime I, the wake is steady and axisymmetric, and it undergoes transition to a steady two-tailed wake in regime II at $\mathit{Re}= 210$. Those regimes are directly analogous to those of a fixed sphere. Once the sphere begins to vibrate at $\mathit{Re}\simeq 270$ in regime III, the wake behaviour is distinct from the fixed-sphere wake. Initially the vibration frequency of the sphere is half the shedding frequency in the wake, with the latter consistent with the fixed-sphere wake frequency. The sphere vibration is not purely periodic but modulated over several base periods. However, at slightly higher Reynolds numbers ($\mathit{Re}\simeq 280$), planar symmetry is broken, and the vibration shifts to the planar normal (or azimuthal) direction, and becomes completely azimuthal at the start of regime IV at $\mathit{Re}= 300$. In comparison, for a fixed sphere, planar symmetry is broken at a much higher Reynolds number of $\mathit{Re}\simeq 375$. Interestingly, planar symmetry returns to the wake for $\mathit{Re}\gt 330$, in regime V, for which the oscillations are again radial, and is maintained until $\mathit{Re}= 450$ or higher. At the same time, the characteristic vortex loops in the wake become symmetrical, i.e. two-sided. For $\mathit{Re}\gt 500$, in regime VI, the trajectory of the sphere becomes irregular, possibly chaotic. That state is maintained over the remaining Reynolds-number range simulated numerically ($\mathit{Re}\leq 800$). Experiments overlapping this Reynolds-number range confirm the amplitude radial oscillations in regime V and the chaotic wandering for regime VI. At still higher Reynolds numbers of $\mathit{Re}\gt 3000$, in regime VII, the trajectories evolve to quasi-circular orbits about the neutral point, with the orbital radius increasing as the Reynolds number is increased. At $\mathit{Re}= 12\hspace{0.167em} 000$, the orbital diameter reaches approximately one sphere diameter. Of interest, this transition sequence is distinct from that for a vertically tethered heavy sphere, which undergoes transition to quasi-circular orbits beyond $\mathit{Re}= 500$.
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Zhu, S., Y. Cai, and S. S. Chen. "Experimental Fluid-Force Coefficients for Wake-Induced Cylinder Vibration." Journal of Engineering Mechanics 121, no. 9 (September 1995): 1003–15. http://dx.doi.org/10.1061/(asce)0733-9399(1995)121:9(1003).
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Assi, Gustavo R. S. "Wake-induced vibration of tandem cylinders of different diameters." Journal of Fluids and Structures 50 (October 2014): 329–39. http://dx.doi.org/10.1016/j.jfluidstructs.2014.07.001.
Full textDissertations / Theses on the topic "Wake Induced Vibration (WIV)"
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Yang, Wenchao. "Two-dimensional Wakes and Fluid-structure Interaction of Circular Cylinders in Cross-flow." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/97563.
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The wake of a bluff body is a representative issue in vortex dynamics that plays a central role in civil engineering, ocean engineering and thermal engineering. In this work, a flowing soap film was used to investigate the wakes of multiple stationary circular cylinders and of a single oscillating cylinder. Corresponding computer simulations were also conducted. Vortex formation of a stationary circular cylinder was analyzed by proper orthogonal decomposition (POD). The POD analysis was used to define an unsteady vortex formation length, which suggests a relationship between the vortex formation length of a single cylinder and the critical spacing of two cylinders in a tandem arrangement. A systematic parametric study of the wake structure was conducted for a controlled transversely oscillating cylinder. Neural network and support vector machine codes assisted the wake classification procedure and the identification of boundaries between different wake regimes. The phase map of the vortex shedding regimes for the (quasi) two-dimensional experiment qualitatively agrees with previous three-dimensional experiments. The critical spacings of two identical tandem circular cylinders in a flowing soap film system were determined using visual inspections of the wake patterns and calculations of the Strouhal frequencies. The dimensionless spacing was both increased and decreased quasi-statically. Hysteresis was observed in the flow patterns and Strouhal numbers. This study appears to provide the first experimental evidence of critical spacing values that agree with published computational results. The wake interaction between a stationary upstream circular disk and a free downstream circular disk was also investigated. With the ability to tie together the wake structure and the object motion, the relationship between energy generation and flow structure in the simplified reduced order model system was studied. The research results find the optimal efficiency of the energy harvesting system by a parametric study.PHD
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Elbanhawy, Amr Yehia Hussein. "On numerical investigations of flow-induced vibration and heat transfer for flow around cylinders." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/on-numerical-investigations-of-flowinduced-vibration-and-heat-transfer-for-flow-around-cylinders(6722ba6d-80de-47f4-a14d-191d4e9ed7fb).html.
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Vortex shedding is an important mechanism, by which the flow around bluff bodies create forces that excite vibratory motion. Vortex-induced vibration (VIV) is studied for a single circular cylinder by means of Computational Fluid Dynamics (CFD) simulations. An arbitrary Lagrangian Eulerian (ALE) formulation is used to achieve the grid deformation needed for VIV. In this thesis, a multifaceted approach is undertaken by which response dynamics and wake interaction are addressed. Four major aspects are considered in the study: the Reynolds number (Re); the mass and damping; the degree-of-freedom for VIV; and the mutual effect between VIV and heat transfer.As attention is paid towards high pre-critical Re flow, the turbulent flow around the cylinder is treated by two turbulence modelling approaches: unsteady Reynolds Averaged Navier Stokes (uRANS), and Large Eddy Simulation (LES). The wake-VIV interaction is analyzed by looking at mean velocities and Reynolds stresses, where decomposition of flow scales is undertaken to explore the evolution of coherent eddy structures, downstream of the cylinder. Conversely, the VIV response is analyzed by considering oscillation amplitude and frequency, in addition to the excitation and inertial dynamics.High turbulence in the separated shear layers disorders the cylinder's VIV response and induces higher amplitudes. The sensitivity for Re is found more pronounced in cylinders with low mass and damping. Meanwhile, VIV is found to enhance wake mixing, and to significantly change the near wake Reynolds stresses. It is suggested that the increase in Re brings a change to the wake patterns, which are known in VIV at lower Re. The kinetic energy production, of near wake eddy structures, is qualitatively altered with the presence of VIV. Furthermore, the surface heat flux is found to cause a noticeable increase in VIV amplitude, as long as it does not disorder the wake correlation. The cylinder's oscillation increases the average value of the Nusselt number (Nu), while the local variance of Nu rises markedly post-separation.
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Mohd, Raizamzamani Bin Md Zain. "Aerodynamic Instabilities of Twin Cables of Cable-stayed Bridge under Wind Actions." Kyoto University, 2018. http://hdl.handle.net/2433/235072.
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Bunjevac, Joseph Antun. "PIV Analysis of Wake Structure of Real Elephant Seal Whiskers." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1501102202600591.
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Manickam, Sureshkumar Eshodarar. "Harnessing Hydro-kinetic Energy from Wake-Induced Vibration (WIV) of Bluff bodies." Thesis, 2018. http://hdl.handle.net/2440/117805.
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In this dissertation, the application Wake-Induced Vibration (WIV) of a bluff body for harnessing the kinetic energy of a fluid flow is presented. WIV arises when a body undergoes vibrations in the wake of an upstream body. This project investigates the WIV of a bluff body (circular cylinder), constrained to vibrate in the transverse direction, operating in the wake produced by a stationary and upstream bluff body. The upstream body serves as an energy concentrator and increases the oscillations experienced by the downstream body. An efficient coupling of the spatially and temporally concentrated energy from the upstream body and the downstream and vibrating body will result in WIV being considered as a viable form of renewable energy. The application of induced vibration due to vortices in harnessing hydrokinetic energy of the fluid is relatively immature and this research work, which is written as a compilation of journal articles, attempts to address major scientific and technological gaps in this field. The wake behind a bluff body augments the hydro-kinetic energy in space as well as time, in the form of a vortex street. Firstly, the kinetic energy distribution of a bluff body (circular cylinder) wake is characterized using numerical modelling, in order to identify the form and density of the available energy. Secondly, the spatial and temporal energy in the wake from different bluff bodies is investigated experimentally to identify a flow energy concentrator that is more suitable for WIV than the circular cylinder. The semicircular, straight-edged triangular, convex-edged triangular and trapezoidal cylinders were chosen for this analysis where the semicircular and convex-edged triangular cylinders were found to augment more temporal energy compared to the circular cylinder. Thirdly, experiments were performed in the water channel to investigate the effects of Reynolds number and separation gaps for the different cross-sections of upstream cylinders. The results indicated that an upstream semicircular cylinder produces more efficient WIV in a downstream circular cylinder compared to an upstream circular cylinder. In addition, both numerical and experimental results indicated that a staggered arrangement with 3 ≤ 𝑥/D ≤ 4 and 1 ≤ 𝑦/D ≤ 2 (here, D is the diameter of the cylinder, and x and y are the horizontal and vertical offsets, respectively) is the optimum arrangement among all test cases to harness the energy of vortices, resulting in a power coefficient of 33%. This was achieved due to the favourable phase lag between the velocity of the cylinder and force imposed by the fluid. Finally, the effect of mass and damping ratio of the downstream cylinder is investigated to optimize the vibration efficiency of the staggered semicircular-circular cylinder WIV system. The results of this test showed that a lower damping ratio results in lower impedance of the system and hence a larger vibration response. The vibration response was also inversely proportional to the mass ratio, however, a mass ratio of 2 – 3 proved to be the most efficient for the WIV system resulting in a maximum efficiency of 49%.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 2018
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Derakhshandeh, Javad Farrokhi. "Harnessing Hydrokinetic Energy from Vortex-Induced Vibration (VIV)." Thesis, 2015. http://hdl.handle.net/2440/119460.
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In this dissertation, the application of Vortex-Induced Vibration (VIV) and Wake-Induced Vibration (WIV) of a bluff body for harnessing the kinetic energy of a fluid flow is presented. The application of induced vibration due to vortices in harnessing hydrokinetic energy of the fluid is relatively immature and this research work, which is written as a compilation of journal articles, attempts to address major scientific and technological gaps in this field. The project spans both VIV and WIV, with a particular attention to the development of a better understanding of the wake behaviour in a tandem configuration and the effect of boundary layers for harnessing the kinetic energy of the flow. Accordingly, two separate coupled test cases of tandem bodies comprising Coupled Circular-Cylinder (CCC) and Coupled Cylinder-Airfoil (CCA) configurations were proposed and investigated. In the first series of tests on the CCC, two circular cylinders were employed to investigate the unsteady wake interactions on the energy yield. The upstream cylinder was fixed, while the downstream one was mounted on a virtual elastic base with one degree of freedom. The virtual elastic system consisted of a motor and a controller, a belt-pulley transmission and a carriage. In the CCC, the influence of the Reynolds number, gap between cylinders and boundary layers on the dynamic response of the downstream cylinder were numerically and experimentally investigated. In a numerical analyse of the system, a dynamic mesh technique within the ANSYS Fluent package was utilized to simulate the dynamic response of the cylinder. The experimental tests confirmed the numerical outcomes and demonstrated that in the WIV mechanisms, a positive kinetic energy transfer from fluid flow to the cylinder was achieved. It is also observed that the dynamic response of the cylinder under the WIV mechanism differs from the dynamic response of VIV. In addition, both numerical and experimental results indicated that a staggered arrangement with 3.5 ≤ x₀/D ≤ 4.5 and 1 ≤ y₀/D ≤ 2 (here, D is the diameter of the cylinder, and x₀ and y₀ are the horizontal and vertical offsets, respectively) is the optimum arrangement among all test cases to harness the energy of vortices, resulting in a power coefficient of 28%. This was achieved due to the favourable phase lag between the velocity of the cylinder and force imposed by the fluid. The results revealed that for the staggered arrangement of the cylinders, the WIV responses can occur at frequencies outside the range in which VIV is observed. In the second series of tests utilizing a CCA, the downstream circular cylinder was replaced by a symmetric airfoil with two degrees of freedom; heave and pitch. The heave degree of freedom employed the same virtual elastic base used for the CCC experiments. The pitch angle of the foil was actively controlled, as opposed to using passive mechanical impedance, since this enables full control over the foil behaviour, thereby facilitating the adjustment of the angle of attack accurately and rapidly. The results of CCA show that both longitudinal and lateral distances play an important role in the Strouhal number, power density and, consequently, the heave response of the airfoil. In addition, it was shown that the circulation of the vortices was influenced by the gap spacing between the cylinder and the airfoil. Furthermore, it was found that an optimum angle of attack of α = 10° is the most efficient for harnessing the energy of vortices with a maximum power coefficient of 30% for cases with 3.5 ≤ x₀/D ≤ 4.5 and 1 ≤ y₀/D ≤ 1.5 arrangements. Such a range is narrower laterally when compared with the optimum arrangement of the CCC. This work provided the foundation for further work to utilize the potential of this technology and further explore the opportunity to harness the vortical power in shallow water and ocean currentsThesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 2015
Conference papers on the topic "Wake Induced Vibration (WIV)"
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Soares, Bruno, and Narakorn Srinil. "Capturing Wake Stiffness in Wake-Induced Vibration of Tandem Cylinders." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18423.
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Abstract When a downstream circular cylinder is in the vicinity of the disturbed wake flow which is originated from the presence of an upstream cylinder, fluid-structure interactions due to vortex- and wake-induced vibrations may coexist. Their combined effects are of practical concern for offshore structures deployed in an array or proximity such as marine risers, pipelines and mooring lines. The wake flow deficit law and wake-induced drag and lift hydrodynamic forces are modelled based on the boundary layer theory, which is modified to account for the oscillation of the upstream cylinder. Unsteady drag and lift forces associated with the vortex-induced vibration (VIV) and wake-induced vibration (WIV) are represented dynamically by van der Pol-type wake oscillators. The present paper proposes a new modelling concept and framework capable of evaluating the combined WIV-VIV of tandem circular cylinders in comparison with experimental data, capturing a key feature of the wake stiffness associated with WIV. An equivalent natural frequency based on the wake stiffness mechanism behaves equivalently to the WIV frequency. Numerical studies show that the downstream cylinder may respond in a multi-frequency scenario at specific reduced velocities. The prediction model captures the wake stiffness trend similar to the experimental observation. The correlation to the wake stiffness concept allows the identification of situations for which the downstream cylinder is mainly governed by the WIV mechanism resulting in largest vibration amplitudes.
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Soares, Bruno, and Narakorn Srinil. "Nonlinear Wake-Induced Vibration of Downstream Cylinder in Staggered Arrangements." In ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-67776.
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Abstract The fluid-structure interaction mechanism of flow past multiple structures in proximity is complex. Depending on the initial spacing between a pair of circular cylinders and the reduced flow velocity parameter, the downstream cylinder may undergo wake-induced vibration (WIV) and/or vortex-induced vibration (VIV). This study presents an advanced numerical time-domain simulation model to predict a two-degree-of-freedom WIV, combined with VIV response, of an elastically mounted rigid circular cylinder behind a stationary cylinder in staggered arrangements. The wake deficit flow is modelled based on the boundary layer theory, whereas the unsteady drag and lift hydrodynamic forces due to the vortex shedding of the downstream cylinder are modelled by using the nonlinear van der Pol wake oscillators. The proposed numerical prediction model is calibrated and compared versus experimental data in the literature. For the initial longitudinal centre-to-centre spacing of 4 diameters and the initial transverse spacing of less than 2 diameters, the downstream cylinder first behaves as an isolated cylinder undergoing VIV at a low deficit flow velocity. With increasing flow velocity and Reynolds number, the downstream cylinder exhibits WIV response with progressively increasing oscillation amplitudes in both cross-flow and in-line directions. For staggered cylinders, the time-varying feature of the mean lift force, directed towards the wake centreline and acting on the downstream cylinder, becomes locally asymmetric through the course of the cylinder motion trajectories. This feature modifies WIV response frequencies and leads to an asymmetric trajectory of the cylinder’s two-directional displacements.
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Sanaati, Bijan, and Naomi Kato. "Wake-Induced Vibration (WIV) of Two Tandem Pre-Tensioned Flexible Cylinders." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-11148.
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It is believed that investigations on flow around pairs of cylinders can provide a better understanding of the interference effects than the cases involving larger numbers of cylinders. Studies that deal with the dynamic responses of multiple flexible cylinders with low mass ratios and high aspect ratios are few because of the complexities in the responses. In this paper, the effects of wake interference on the dynamic responses of two pre-tensioned flexible cylinders in tandem arrangement subjected to uniform cross-flow are investigated. The analysis results of the tandem cylinders are presented and compared with an isolated flexible cylinder. Two flexible cylinders of the same size, properties, and pretensions were tested at four different centre-to-centre separation distances, namely, 2.75, 5.5, 8.25 and 11 diameters. Reynolds number range is from 1400 to 20000 (subcritical regime). The aspect ratio of the cylinders is 162 (length over diameter). Mass ratio (cylinders mass over displaced water) is 1.17. The amplitude ratio of the CF vibration of the downstream cylinder, IL deflections of both cylinders, frequency responses in both CF and inline (IL) directions were analyzed. For all the examined separation distances, the downstream cylinder does not show build-up of upper branch (within the lock-in region of the classical VIV of the isolated cylinder). The initial distance between the tandem cylinders cannot remain constant. The distance decreases with reduced velocity because of the unequal IL deflection of tandem cylinders. From the CF frequency response of the lift (transverse) force of downstream cylinder, the highest vibration amplitude at all the separation distances occurs whenever their frequencies transitioned into second modal value. The frequency responses of the upstream cylinder cannot be greatly affected by the downstream cylinder even for small separations in contrast to the downstream cylinder.
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E´tienne, Ste´phane, and Dominique Pelletier. "The Low Reynolds Number Limit of Vortex and Wake-Induced Vibrations." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-30387.
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Vortex and wake induced vibrations (VIV/WIV) of a circular cylinder at low values of the Reynolds number (Re) are simulated by means of a fully coupled fluid-structure interaction numerical model based on the finite element method. It is shown that VIV/WIV could occur far below the first Hopf bifurcation (Re <47). The main objective of this study is to determine the limiting Reynolds-Reduced velocity (Ur) curve that separates the non-vibrational area from the possible vibrations occurrence area. We assume that by taking a zero mass cylinder and zero structural damping we will obtain the low limit of vibrations in terms of Re and Ur. It is shown in particular that transverse vibrations could occur for reduced velocities larger than 40 and not below 3.5.
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Assi, Gustavo R. S., Peter W. Bearman, and Julio R. Meneghini. "Wake-Induced Vibration of a Pair of Circular Cylinders and Its Dependency on Reynolds Number." In ASME 2010 3rd Joint US-European Fluids Engineering Summer Meeting collocated with 8th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2010. http://dx.doi.org/10.1115/fedsm-icnmm2010-31278.
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This paper investigates the wake-induced vibration (WIV) of the downstream cylinder of a pair as far as its dependency of Reynolds number is concerned. Experiments have been conducted in a circulating water channel with a rigid cylinder elastically mounted to respond with oscillations in the cross-flow direction. Various sets of coil springs were employed to vary the reduced velocity of the system maintaining constant the Reynolds number. Experiments performed with a cylinder mounted without springs provided the idealised case of reduced velocity equal to infinity. We conclude that the amplitude of the WIV response has a strong dependency on Reynolds number even within the small range between Re = 2 × 103 and 2.5 × 104. If the reduced velocity parameter is isolated — by making it equal to infinity, for instance — the Re-dependency still dominates over the behaviour of the response.
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Kang, Zhuang, Weixing Liu, and Wei Qin. "Vortex-Induced Vibration Experiment Research of Two Cylinders in Tandem Arrangement." In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10471.
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The vortex-induced vibration of tandem arrangement of two cylinders compared with the single cylinder is more complicated, The double cylinder arranged in tandem, which is free to move in two degrees of freedom respectively, and which has low mass and damping. The present study shows that a critical centre-to-centre spacing can be used to distinguish the far and near wake interference. The streams in this test were uniform flow, ranging from 0.2m/s to 0.8m/s with the interval of 0.1m/s. The Re numbers are ranging from 22000 to 88000. The mass ratio of cylinder is low. For far wake interference, the downstream cylinder shows large amplitudes of response, therefore the wake induced vibration (WIV) is found. For near wake interference, both the upstream cylinder and downstream cylinder are exposed to an evident phenomenon of VIV, but the amplitude of upstream and downstream are less than that of single cylinders in cross-flow direction and in-line direction. We found the critical spacing to be 3.4 to 4.9.
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Joshi, Vaibhav, Bin Liu, and Rajeev K. Jaiman. "Flow-Induced Vibrations of Riser Array System." In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54695.
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When a riser array system is subjected to a uniform flow, an unstable flow-induced vibration commonly occurs among cylinders, generally called fluid-elastic instability. It can cause long-term or short-term damage to the riser array system. A numerical investigation has been performed in the present study. Generally, flow-induced vibrations include vortex-induced vibration (VIV), wake-induced vibration (WIV), jet switching, turbulent buffeting and fluid-elastic instability. The dynamic interactions among the fluid-induced vibrations, wake interference and proximity interference pose difficulties in the design and operation of the riser array system. The dynamics of a riser array system is very different from that of basic canonical configurations such as side-by-side, tandem and staggered arrangements. In a riser array system, the interferences come from all possible nearby constituent risers. There is a synchronization phenomenon among the cylinders, which may lead to detrimental collisions and short-term failures. It is known that the vortex-induced vibration (VIV) of an isolated circular cylinder is self-limiting. An extensive vibration occurs in the lock-in region within which the frequency of the vortex shedding matches the structural frequency of the immersed structure. In a riser array system, there is a point at which the vibration of cylinder suddenly increases. The vibration of the constituent risers increases without bound with the increment of the free-stream velocity. This free-stream velocity is defined as the critical velocity. The interference not only comes from the inline and cross-flow directions, but also the wake interference from the diagonal upstream risers. In a riser array system, each riser vibrates independently. However, there is symmetry of frequency spectrum observed about the inline direction along the middle row of the risers. In this study, the dynamic response of the different risers in the array system is investigated with the help of the amplitude response results from the canonical arrangements (side-by-side and tandem) and wake flow structures. The long top-tensioned riser system can be idealized by two-dimensional elastically mounted cylinders to solve the complex fluid-structure interaction problem. The dynamic response of a typical riser array system has been analyzed at low and high Reynolds number. It is encouraging to see that the results reported in the present investigation can provide useful insight and suggestions in the design and optimization of riser systems to avoid collisions and various long-or short-term failures.
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Assi, Gustavo R. S., and Peter W. Bearman. "VIV and WIV Suppression With Parallel Control Plates on a Pair of Circular Cylinders in Tandem." In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79081.
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Experiments have been carried out on two-dimensional devices fitted to a rigid length of circular cylinder to investigate the efficiency of pivoting parallel plates as wake-induced vibration suppressors. Measurements are presented for a circular cylinder with low mass and damping which is free to respond in the cross-flow direction. It is shown how VIV and WIV can be practically eliminated by using free to rotate parallel plates on a pair of tandem cylinders. Unlike helical strakes, the device achieves VIV suppression with 33% drag reduction when compare to a pair of fixed tandem cylinders at the same Reynolds number. These results prove that suppressors based on parallel plates have great potential to suppress VIV and WIV of offshore structures with considerable drag reduction.
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Guo, Kai, Yuxuan Cheng, Xiantao Fan, Hongsheng Zhang, and Wei Tan. "An Investigation on Vortex Induced Vibration and Wake Induced Galloping in Tandem Cylinders System." In ASME 2022 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/pvp2022-84537.
Full textAbstract:
Abstract The flow-induced vibration (FIV) of multi cylinders is a problem involving the safety of fluid engineering and energy harvesting. Due to the effect of wake galloping and vortex induced vibration (VIV), the mechanism of two tandem cylinders is more complex than that of a single cylinder. In this study, the vibration modes of two tandem cylinders with different spans (L/D = 1.5–4.0) are investigated at subcritical Reynolds number and high mass damping ratio through wind tunnel tests. In the experiment, the cylinders are free to vibrate in the transverse and in-flow direction. The characteristics of the vibration amplitude and vibration frequency response are discussed with the vibration mode. The results show that the vibration mode is related to the reduced pitches between the cylinders. The vibration of the two tandem cylinder system is combines results of vortex induced vibration and wake induced galloping (WIG). When the span is lower than 2.0, the galloping effect is more obvious than that of larger spans cylinders at the experiment mass damping parameters. The two cylinders turn to vibrate separately as the span grows larger.
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Tofa, M. Mobassher, Adi Maimun, and Yasser M. Ahmed. "Effect of Upstream Cylinder’s Oscillation Frequency on Downstream Cylinder’s Vortex Induced Vibration." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66990.
Full textAbstract:
Vortex induced vibration or widely known as VIV, is a very complex hydrodynamic phenomenon. There are relatively very few experimental and numerical references for oscillating pair of cylinders because of the early assumption that the interference between the two cylinders is weak and thus each of the cylinders may have the same behavior as found in the case of a single cylinder, but recent researches showed this assumption was not true. For tandem arrangement, several parameters govern the nature of VIV of downstream cylinders, such as spacing, upstream cylinders VIV amplitude etc. The nature of downstream cylinders response isn’t same as classical VIV or WIV (wake induced vibration). Oscillation frequency of a cylinder subjected to flow induced vibration is one of the important characteristics Oscillation frequency is highly dependent on natural frequency of the cylinder. By changing spring stiffness or mass ratio, natural frequency can be altered. The aim of this study is to investigate the effect of upstream cylinder’s oscillation frequency on the vibration of downstream cylinder. Numerical simulations have been conducted to understand the nature of vortex induced vibration (VIV) of a pair cylinder in tandem arrangement at high Reynolds numbers. Cylinders were subjected to uniform flows in sub-critical flow regime and have been allowed to oscillate in cross flow direction only. The spacing between the upstream and downstream cylinders was four times of the cylinder diameter. The oscillation frequency of the upstream cylinder has been altered by varying the mass ratio of the upstream cylinder. It was found that for same Reynolds number, downstream cylinder’s VIV amplitude is increased quite significantly if the upstream cylinder oscillates relatively slowly. The shear stress transport detached eddy turbulence model has been used for simulating the turbulent flow around the two cylinders. An advanced mesh movement known as “mesh morphing” model was employed to lessen the requirement for re-meshing which help to increase the accuracy of the prediction. Calculation of accurate results due to large domain deformations was achieved by re-positioning existing mesh points. The numerical results of a single cylinder subjected to one degree of freedom (1DOF) vibration have been compared with the available experimental results to validate the present study. The study is important in terms of designing VIVACE (Vortex Induced Vibration for Aquatic Clean Energy) converter for low speed current. In recent past, multiple cylinders have been used for VIVACE converter. So, the study of VIV of two equal-diameter cylinders in tandem arrangement at low current speed is very significant.