Vortex-Excited Vibrations of Uniform Pivoted Cylinders in Uniform and Shear Flow

Balasubramanian, Sridhar; Skop, Richard A.; Haan, Fred L.; Szewczyk, Albin A.

doi:10.1006/jfls.1999.0255

Cited by 24 publications

(24 citation statements)

References 15 publications

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“…The vortex shedding frequency and thus the timing of fluid forcing at different sections along the span of pivoted cylinders is not necessarily consistent. Distinct change in the predominant vortex shedding frequency along the span of pivoted circular cylinders has been found to occur (Balasubramanian et al 2000). In close proximity to the cylinder pivot, the vortex shedding occurred primarily at the Strouhal frequency and, along the majority of the span, shedding frequency was controlled by the cylinder oscillation frequency during the VIV synchronization region.…”

Section: Introductionmentioning

confidence: 93%

“…no splitter-plate) circular cylinder, that by definition has non-uniform spanwise vibration amplitudes (see e.g. Balasubramanian et al 2000;Fleming and Williamson 2005;Voorhees et al 2008;Kheirkhah, Yarusevych and Narasimhan 2012). However, to the present authors' knowledge, little, if any, studies exist that have investigated the vibration response of the pivoted rigid circular cylinder with attached wake splitter-plate.…”

Section: Introductionmentioning

confidence: 97%

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Flow-induced vibration characteristics of pivoted cylinders with splitter-plates

Johnstone

Stappenbelt

2015

Australian Journal of Mechanical Engineering

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Experiments have been performed to investigate the characteristics of the flow-induced vibration response of pivoted rigid circular cylinders with attached wake splitter-plates. Motion of the cylinder was constrained to the plane normal to the flow direction and the response characteristics were assessed in regard to the peak angular excursion of the cylinder and the frequency of the cylinder oscillation. Across the range of splitter-plate lengths tested 0.5 < l/D ≤ 3.0, large angular excursions of a galloping-type response were observed together with reduction in the oscillation frequency of the cylinder with increased splitter-plate length.ARTICLE HISTORY

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 97%

Flow-induced vibration characteristics of pivoted cylinders with splitter-plates

Johnstone

Stappenbelt

2015

Australian Journal of Mechanical Engineering

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“…(5) has been introduced by Skop and Balasubramanian [16] to account for the fluctuation of lift coefficient. By following the extended study on sheared flows by Balasubramanian et al [17], the empirical wake variable Q in Eq. (5) is governed by the following van der Pol diffusive wake oscillator ( )…”

Section: Nonlinear Equations Of Riser Motion and Wake Oscillatormentioning

confidence: 99%

“…where C L0 is the lift coefficient of fixed cylinder, F and G are the scaling wake coefficients, and τ is the diffusion parameter which is given, based on a few experimental results, by [17] ( )…”

Section: Nonlinear Equations Of Riser Motion and Wake Oscillatormentioning

confidence: 99%

Numerical and Experimental Comparisons of Vortex-Induced Vibrations of Marine Risers in Uniform/Sheared Currents

Srinil

O’Brien²,

Wiercigroch

2010

29th International Conference on Ocean, Offshore and Arctic Engineering: Volume 6

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This version is available at https://strathprints.strath.ac.uk/18595/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output. The nonlinear equations governing riser axial/transversal motions are derived based on a top-tensioned beam model with typical pinned-pinned boundary conditions. The riser geometric nonlinearities owing to possible large dynamic displacements and multi-mode interactions are accounted for. To approximate the space-time varying lift force, the empirical hydrodynamic model, based on a nonlinear van der Pol wake oscillator with a distributed diffusive term, is used. A low-dimensional dynamic model and computationally-robust time-domain tool are then developed to evaluate the multi-mode fluid-riser interactions. These are very useful in dealing with large parametric studies involving varying system parameters.Comparisons of numerical and experimental results are performed by estimating riser response amplitudes and fatigue damage indices. Both linear and nonlinear risers are considered in the present numerical model whereas only linear riser has been considered by a referenced literature in the reconstruction of experimental displacements through measured strains. It is found that riser geometric nonlinearities play a significant role in both numerical simulations and comparisons with experiment post-processed results. In some cases, quantitative/qualitative discrepancies in riser response predictions are remarkable with linear vs. nonlinear models. These may be recognized as one of the factors why recent numerical and experimental comparisons in literature have been unsuccessful.

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“…Investigators focusing on this method include Goswami et al (1993b) and Skop & Balasubramanian (1995a,b). Balasubramanian & Skop (1999) reported improved results when including a stall parameter with the van der Pol oscillator. Barhoush et al (1995) combined a van der Pol oscillator approach with a two-dimensional finite element mesh, resulting in a good representation of steady-state vortex-induced vibration behaviour at 'high computational cost'.…”

Section: (I) Wake-body Coupled Modelsmentioning

confidence: 99%

Modelling vortex-induced fluid–structure interaction

Benaroya

Gabbai

2007

Phil. Trans. R. Soc. A.

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The principal goal of this research is developing physics-based, reduced-order, analytical models of nonlinear fluid-structure interactions associated with offshore structures. Our primary focus is to generalize the Hamilton's variational framework so that systems of flowoscillator equations can be derived from first principles. This is an extension of earlier work that led to a single energy equation describing the fluid-structure interaction. It is demonstrated here that flow-oscillator models are a subclass of the general, physical-based framework. A flow-oscillator model is a reduced-order mechanical model, generally comprising two mechanical oscillators, one modelling the structural oscillation and the other a nonlinear oscillator representing the fluid behaviour coupled to the structural motion.Reduced-order analytical model development continues to be carried out using a Hamilton's principle-based variational approach. This provides flexibility in the long run for generalizing the modelling paradigm to complex, three-dimensional problems with multiple degrees of freedom, although such extension is very difficult. As both experimental and analytical capabilities advance, the critical research path to developing and implementing fluid-structure interaction models entails -formulating generalized equations of motion, as a superset of the flow-oscillator models; and -developing experimentally derived, semi-analytical functions to describe key terms in the governing equations of motion. The developed variational approach yields a system of governing equations. This will allow modelling of multiple d.f. systems. The extensions derived generalize the Hamilton's variational formulation for such problems. The Navier-Stokes equations are derived and coupled to the structural oscillator. This general model has been shown to be a superset of the flow-oscillator model. Based on different assumptions, one can derive a variety of flowoscillator models.

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Vortex-Excited Vibrations of Uniform Pivoted Cylinders in Uniform and Shear Flow

Cited by 24 publications

References 15 publications

Flow-induced vibration characteristics of pivoted cylinders with splitter-plates

Flow-induced vibration characteristics of pivoted cylinders with splitter-plates

Numerical and Experimental Comparisons of Vortex-Induced Vibrations of Marine Risers in Uniform/Sheared Currents

Modelling vortex-induced fluid–structure interaction

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