The vortexinduced vibrations viv of a rigid circular cylinder, mounted on an elastic. Vortex induced vibrationomics international journal of. The fluid loading on the vibrating solid and resulting dynamics are computed using an appropriate wakeoscillator model, allowing one to perform a systematic parametric study of the efficiency. The study can also include fiv excitation of smallbore piping and components in the flow, such as thermowells. Energy generation from vortex induced vibrations guided by.
To this end, viv is described by a onedegreeoffreedom model where fluid forces are introduced from experimental data from forced vibration tests. Pdf numerical studies on piezoelectric energy harvesting. Flowinduced vibrations is constructed as an engineering guide primarily based on research sponsored by the volkswagen foundation located in hannover, germany. Nonuniform currents effect the spanwise vortex shedding on a cable or riser. Numerical modelling of vortex induced vibrations in submarine pipelines f. Vortexinduced vibration viv of a sphere represents one of the most generic fundamental fluidstructure interaction problems. Also, depending on the intensity of the noise coefficient, the probability density functions of the response amplitude also undergo qualitative and quantitative. We investigate the validity of the independence principle for fixed yawed circular cylinders and free yawed circular rigid cylinders subject to vortexinduced vibrations viv at subcritical reynolds number using direct numerical simulation dns.
The lift force may induce crossflow vibrations and the drag force may induce inline vibrations. Typically, these vibrations are very small and users of digital vortex flow meters need not concern themselves with this mode of vibration. Vortexinduced vibration is a major cause of fatigue failure in submarine oil and gas pipelines and steel catenary risers. Bladeless windmill, vortex induced vibrations, vortex shedding, renewable energy sources. Vortexinduced vibration of a rotating sphere cambridge core. Vortex and wake induced vibrations in an array of cylinders. Numerical modelling of vortex induced vibrations in. We investigate the validity of the independence principle for fixed yawed circular cylinders and free yawed circular rigid cylinders subject to vortex induced vibrations viv at subcritical reynolds number using direct numerical simulation dns. This phenomenon is called vortex induced vibration viv blevins, 2001.
This is the real viv this is vortexinduced vibration o forced oscillations occurs at velocities and amplitudes which are preset and can be controlled independently of fluid velocity. This paper describes the design of passive dampers for guyed masts and steel chimneys in conditions where the natural frequencies of the structure can not be determined accurately. Flow induced vibrations is constructed as an engineering guide primarily based on research sponsored by the volkswagen foundation located in hannover, germany. Flowinduced vibrations of offshore flare towers and flare booms g. On the study of vortexinduced vibration of a cylinder with. Hence, if dynamic loads can occur, the free span may oscillate and time varying stresses may give unacceptable fatigue damage. The paper reports a case study of wind induced vor tex shedding vibrations of a steel light mast.
Here, vortexinduced vibrations vivs of a circular cylinder are analyzed as a potential source for energy harvesting. Computation of vortexinduced vibrations of long structures. Structures subjected to fluid flow are usually designed to minimize fatigue caused by vortex induced vibrations. Two large recirculating pumps combine to give a maximum capacity of 850. Vortex induced vibrations viv forms the basis of the hydrokinetic energy converter. Vortexinduced vibrations of streamlined single box girder bridge. Optimal energy harvesting from vortexinduced vibrations of cables guillaume o. Feb 17, 2016 vortex induced vibrations of free span pipelines pipelines from offshore petroleum fields must frequently pass over areas with uneven seafloor. The challenge for the industry is then to verify that such spans can sustain the in. A criterion for assessing wind induced crossflow vortex vibrations in wind sensitive structures author. The paper studies the scope and feasibility of the bladeless windmill. Modeling of vortex induced vibration based hydrokinetic energy converter krishna manasa rao1 and ashray gururaja manur2 1, 2department of electrical and electronics engineering, sri jayachamarajendra college of engineering, india abstract. Wind, vortex shedding, vibrations, acceleration, fullscale data. Studies of vortex induced vibration on the naca0015.
Vortexinduced vibrations of an inclined cylinder in flow. Master thesis wind induced vibrations of fruhsc bridge decks. Three dimensional effects shear layer instabilities as well as longitudinal braid vortices lead to transition from laminar to turbulent flow in cylinder wakes. These flowrelated phenomena are called flowinduced vibration.
Viv has received much attention by the industry in the last decade. Study of vortex induced vibrations for harvesting energy. As such these vortices create vortexinduced vibration. Noise control engineering journal, flowinduced vibrations researchersdecided it was time to compile the research reported on the phenomenon for the past quarter century, emphasizing information that can be used in designing systemsthe second edition also contains new chapters on vibrations in rotary machines, and vibrations in fluid. There are a staggering number of different disciplines and approaches to this subject, and from my own perspective this is one of the best guides published. Vortex induced vibration viv is an important source of fatigue damage of offshore oil exploration and production risers. Optimal energy harvesting from vortex induced vibrations of cables guillaume o. Flow induced vibration fiv is an important phenomenon, by which the flow around bluff bodies creates forces that excite vibration. Josephs college of engineering and technology, palai. Energy generation from vortex induced vibrations report.
The vibrations are examined, full scale observations reported and the coun termeasures devised to. This phenomenon is called vortexinduced vibration viv blevins, 2001. Bearman department of aeronautics, imperial college, london sw7 2az, uk vortexinduced vibration of solid structures has been known since ancient times, and remains a very important problem of. Flowinduced vibrations of offshore flare towers and flare booms. If the vortex shedding frequency coincides with a natural frequency of vibration of a member. Vortexinduced vibrations on bridges the interaction mechanism in. Calculation of vortex induced vibrations viv of slender marine structures like risers, free span pipelines, cables subjected to ocean current. Introduction the issue of global climate change and the growing energy demand induce a need for innovative energy harvesting devices. But here, we try to increase the vibrations in order to convert vortex induced vibrations into electricity. Pdf the paper reports a case study of wind induced vor tex. Vortex induced vibration of bluff structures is one of the key issues in riser and pipeline designs.
In such cases the pipeline may have free spans when crossing depressions. Introduction encountered in many engineering situations civil marine structures in windwater flow may undergo large oscillations also referred as vortexinduced vibration viv. In this paper, the possibility to harvest energy from a flow using vortexinduced vibrations viv of a tensioned flexible cable is analyzed. There are a staggering number of different disciplines and approaches to this subject, and from my own perspective this is. Computation of vortexinduced vibrations of long structures using a wake oscillator model. Frequent wind induced vibration may induce fatigue damage to the cables. Since vortexinduced vibration can lead to structural failure, numerous studies have focused on understanding the underlying principles of viv and its suppression. These slender structures experience both current flow and topend vessel motions, which give rise to the flowstructure relative motion and cause viv. Only recently has the idea been proposed to enhance the vibrations in order to maximize energy extraction from the fluid. Vortexinduced vibrations of an inclined cylinder in flow a thesis presented by anil b. Therefore it is highly desirable to reduce the wind induced vibrations for the optimized design and durability of the cablestayed bridges. Vortex induced vibration is a wellknown fluid flow phenomenon.
Flowinduced vibration fiv is an important phenomenon, by which the flow around bluff bodies creates forces that excite vibration. Analysis of vortexinduced vibrations of risers masters thesis in applied mechanics anton gustafsson department of applied mechanics division of material and computational mechanics chalmers university of technology abstract fluidstructure interaction fsi is a challenging eld in engineering analysis and many aspects must be taken into. We compare forces on the cylinder and cylinder responses for different angles of yaw and reduced velocities, and investigate the value of the. There are many studies on the vortexinduced vibrations of a cylindrical body, but almost none concerned with such vibrations for a sphere, despite the fact that tethered bodies are a common. Journal of fluids and structures iowa state university. Most of the practically used structures are bluff in nature such as bridges, buildings, heat exchangers tubes, cooling studies of vortex induced vibration on the naca0015 amir h. Furthermore, highlight large scale coherent structures dynamics when the staggering angle is varied. Vortexinduced vibrations may occur on slender structures such as. Flowinduced vibration fiv analysis vortex shedding. Flowinduced vibrations of offshore flare towers and flare. Vortex induced vibrations of free span pipelines pipelines from offshore petroleum fields must frequently pass over areas with uneven seafloor. Vortex induced vibrations can be a serious concern for operations and for the structural integrity of mooring cables, towing hawsers, marine risers, and moored bluff structures, such as spar buoys. Pdf vortexinduced vibrations of three staggered circular cylinders.
Nov 11, 2014 energy generation from vortex induced vibrations 1. As such these vortices create vortex induced vibration. Vortex induced vibration, fluidelastic instability and vibrations due to random pressure fluctuations. Vortexinduced vibration of two elastically coupled. We particularly investigate the conversion of vortexinduced vibrations to electric power under different operating conditions. This leads to cells of vortex shedding with some length, lc.
Flowinduced vibration, or vortex shedding, is due to high flow velocities such as in a piping dead leg of a centrifugal compressor system. The worldleading author team doesnt assume prior knowledge of mathematical methods and provide the reader with information on the basics of modeling. It was found that the interference between the two cylinders was very weak if the centertocenter gap exceeded 3. Flow induced vibrations of offshore flare towers and flare booms g. A criterion for assessing health and safety executive. On the other end of the tank, two flow guides served to merge flow from the. Digital vortex flowmeters, bu the very nature of their principle of operation create vorticies. Nov 11, 2014 energy generation from vortex induced vibrations report 1. This study evaluates vortex shedding and potential vibration across dead leg branches.
Activepassive controls and energy harvesting from vortex. After the response is modelled for each type, the responses. The topend vessel motion causes the riser to oscillate and the. The riser motion is initiated by viv vortex induced vibrations and if the riser motion is equal to one of the natural frequencies the fatigue life decreases rapidly. The wake is essentially a karman vortex street, but is actually generated by a body that has no mass, no spring, and no damping.
Coupling of structure and wake oscillators in vortexinduced. The rigid cylinder is elastically supported and oscillates in both inline and crosswise. Therefore it is highly desirable to reduce the windinduced vibrations for the optimized design and durability of the cablestayed bridges. Vortex induced vibrations viv are an important source of fatigue damage for risers in the oil and gas industry.
Optimal energy harvesting from vortexinduced vibrations of. Investigate how the vortexinduced vibrations are affected by the interaction of elastically mounted multiple cylinders, confined in a rectangular channel. The frequency of shedding can be different along length. The information below is extracted from the wikipedia pages referring to this in. For a vibrating cylinder, the vortex shedding synchronizes with. This paper presents numerical studies on piezoelectric energy harvesting from vortex induced vibrations. Vortexinduced vibrations viv a cylinder oscillating in a stream can. We consider the piezoelectric option because it can be used to harvest energy over a wide range of frequencies and can be easily implemented. The hydrodynamic model in vivana software is based on empirical coefficients, while the structural model applies a nonlinear 3dimensional finite element formulation. In this paper, the possibility to harvest energy from a flow using vortex induced vibrations viv of a tensioned flexible cable is analyzed. Wind induced vibrations of fruhsc bridge decks 7 e. Frequent windinduced vibration may induce fatigue damage to the cables. By carrying out laboratory experiments, huerahuarte and gharib, 2011a, huerahuarte and gharib, 2011b investigated vortexinduced vibration of two flexible cylinders in sidebyside and tandem arrangements. Pdf vortexinduced vibrations of three staggered circular cylinders are.
In such conditions, an account should be taken of an offset in the frequencytuning of the. This book explains how and why such vibrations happen and provides hints and tips on how to avoid them in future plant design. Pipelines from offshore petroleum fields must frequently pass over areas with uneven seafloor. Vortexinduced vibrations 415 red100 computations undertaken by tony leonard, doug shiels, and anatol roshko at caltech shiels et al. Vortexinduced vibrations viv are an important source of fatigue damage for risers in the oil and gas industry. However, in order to correctly reproduce the influence of the traffic on the bridge deck, it is required the use of multislice dynamic models, which combine in the. When marine risers are designed in a tandem arrangement, two aspects of fiv including vortex induced vibration viv and wakeinduced vibration wiv are very important, resulting in strong vibrations and fatigue damage. When marine risers are designed in a tandem arrangement, two aspects of fiv including vortex induced vibration viv and wake induced vibration wiv are very important, resulting in strong vibrations and fatigue damage. Numerical prediction of flow induced vibrations in nuclear. Instead of minimizing the effect of vivs, as is usual in mechanical engineering projects, our project seeks to maximize vortex induced vibrations to effectively convert wind energy into mechanical energy. Understanding and predicting vortexinduced vibrations. Vortexinduced vibration of bluff structures is one of the key issues in riser and pipeline designs. Experimental studies of the vortexinduced vibration of circular cylinders have provided many fundamental.
Jain submitted to the graduate school of the university of massachusetts amherst in partial fulfillment. Results from recent viv experiments by vandiver et al. Modeling of vortex induced vibration based hydrokinetic. Vortexinduced vibrations of a rigid circular cylinder oatao. Here, vortex induced vibrations vivs of a circular cylinder are analyzed as a potential source for energy harvesting. Effects of oblique inflow in vortexinduced vibrations. Williamson fluid dynamics research laboratories cornell university supported by the office of naval research. Energy generation from vortex induced vibrations 1. The turbulent spots merge giving a fully turbulent boundary layer, and thus. Time domain analysis of vortex induced vibrations viv ntnu. The hydrodynamic model in vivana software is based on empirical coefficients, while the structural model applies a nonlinear 3. Vortexinduced vibrations can be a serious concern for operations and for the structural integrity of mooring cables, towing hawsers, marine risers, and moored bluff structures, such as spar buoys. Flow induced vibration, or vortex shedding, is due to high flow velocities such as in a piping dead leg of a centrifugal compressor system.
586 1340 526 747 114 353 647 919 506 1031 1552 510 161 357 182 1200 1173 725 859 856 3 686 1060 1418 46 993 1609 355 1389 321 67 32 1358 1125 535