A cable galloping model for thin ice accretions

McComber, Pierre; Paradis, A.

doi:10.1016/s0169-8095(97)00047-1

Cited by 50 publications

(11 citation statements)

References 4 publications

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“…Blevins (1977), Blevins and Iwan (1974), Desai et al (1990), McComber and Paradis (1998). However, in many cases there are similar structural conditions for translational motions in the two orthogonal planes normal to the cylinder axis and rotational motion may not occur simultaneously, so it is appropriate to consider pure translational 2DOF galloping.…”

Section: Introductionmentioning

confidence: 99%

Misconceptions and Generalizations of the Den Hartog Galloping Criterion

Nikitas

Macdonald

2014

J. Eng. Mech.

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Classical quasi-steady galloping analysis deals exclusively with cases of across-wind vibrations, leaving aside the more general situation where the wind and motion may not be normal. This can arise in many circumstances, such as the motion of a power transmission cable about its equilibrium configuration, which is swayed from the vertical plane due to the mean wind, or for a tall slender structure in a skewed wind. Furthermore the generalisation to such situations, when this had been made, has only considered special issues.In this paper the correct equations for the quasi-steady aerodynamic damping coefficients for the rotated system or wind are derived, and differences from other variants are highlighted. Motion in two orthogonal structural planes is considered, potentially giving coupled translational galloping, for which previous analysis has often been limited or has even arrived at erroneous conclusions. For the two-degree-of-freedom case, the behaviour is dependent on the structural as well as aerodynamic parameters, in particular the orientation of the principal structural axes and the relative natural frequencies in the two planes. For the first time, differences in the aerodynamic damping and zones of galloping instability are quantified, between solutions from the correct perfectly tuned, well detuned and classical Den Hartog equations (and also an incorrect generalisation of it), for a variety of typical cross-sectional shapes. It is found that although the Den Hartog summation often gives a reasonable estimate for the actual aerodynamic damping even for the rotated situation, in some circumstances the differences can be quite large.

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Section: Introductionmentioning

confidence: 99%

Misconceptions and Generalizations of the Den Hartog Galloping Criterion

Nikitas

Macdonald

2014

J. Eng. Mech.

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“…Galloping instabilities, either transverse or torsional, have got the attention of many researchers because of their impact on very common engineering problems related to ice accretion on electric transmission lines [1][2][3], traffic signal gantries and structures [4][5][6], catenary leads and many other two-dimensional applications. Recently, the interest in the galloping phenomena has increased because of their potential use as a renewable energy source.…”

Section: Introductionmentioning

confidence: 99%

Transverse galloping of two-dimensional bodies having a rhombic cross-section

Ibarra¹,

Sorribes²,

Alonso³

et al. 2014

Journal of Sound and Vibration

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a b s t r a c tTransverse galloping is a type of aeroelastic instability characterized by oscillations perpendicular to wind direction, large amplitude and low frequency, which appears in some elastic two-dimensional bluff bodies when they are subjected to an incident flow, provided that the flow velocity exceeds a threshold critical value. Understanding the galloping phenomenon of different cross-sectional geometries is important in a number of engineering applications: for energy harvesting applications the interest relies on strongly unstable configurations but in other cases the purpose is to avoid this type of aeroelastic phenomenon. In this paper the aim is to analyze the transverse galloping behavior of rhombic bodies to understand, on the one hand, the dependence of the instability with a geometrical parameter such as the relative thickness and, on the other hand, why this cross-section shape, that is generally unstable, shows a small range of relative thickness values where it is stable. Particularly, the non-galloping rhombus-shaped prism's behavior is revised through wind tunnel experiments. The bodies are allowed to freely move perpendicularly to the incoming flow and the amplitude of movement and pressure distributions on the surfaces is measured.

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“…is the torsional strain of the transmission line, = ∂ ∂ ⁄ . By the aerodynamic model of the iced transmission line and the effect of the thin ice accretions [16], the kinetic energy and the virtual work are given by:…”

Section: The Dynamic Modelmentioning

confidence: 99%

Galloping behavior analysis of transmission line with thin ice accretions

Cui¹,

Liu²,

Zhang³

et al. 2018

Vib. proced.

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A dynamic model of a galloping transmission line able to describe for the coupling of its longitudinal, in-plane, out-of-plane and torsional vibrations is established. It also considers the effects of geometrical nonlinearity and aerodynamic nonlinearity. By the static configuration, the reduced model is obtained. Then, the equations of motion are obtained through the Galerkin method. It contains two in-plane, two out-of-plane and two torsional components. By numerical calculation, the maximum amplitudes at wind speeds are drawn and the galloping behavior of transmission line with thin ice accretions is analyzed. The obtained results show that the second galloping mode is more triggered. The double-mode galloping occurs in all motions, in which the maximum amplitude is bigger than in single-mode galloping. And the double-mode galloping presents the track of inclined '8' in longitudinal direction.

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A cable galloping model for thin ice accretions

Cited by 50 publications

References 4 publications

Misconceptions and Generalizations of the Den Hartog Galloping Criterion

Misconceptions and Generalizations of the Den Hartog Galloping Criterion

Transverse galloping of two-dimensional bodies having a rhombic cross-section

Galloping behavior analysis of transmission line with thin ice accretions

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