On the galloping instability of two-dimensional bodies having elliptical cross-sections

Alonso, G.; Meseguer, José; Sanz-Andrés, Ángel; Valero, Eusebio

doi:10.1016/j.jweia.2010.02.002

Cited by 45 publications

(27 citation statements)

References 10 publications

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“…In the case of galloping, the literature is biased through prone to gallop bodies; a large number of papers dealing with the galloping properties of a wide spectrum of geometries have been published [9,[15][16][17][18]. Other cases of interest are the twodimensional bodies with highly attenuated oscillations and those which do not gallop.…”

Section: Introductionmentioning

confidence: 99%

“…Such analysis has been performed at IDR/UPM experimental facilities and the galloping properties of different families of two-dimensional bodies with different cross-section shapes have been published (triangles, rhombi, biconvex, elliptical, rectangles, etc. [15][16][17]). These bodies show transverse galloping instability in certain ranges of the angle of attack, and they are stable outside these specific limits.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

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

Self Cite

View full text Add to dashboard Cite

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“…where, F d , F l = Mean drag and lift forces, respectively; C d , C l = Mean drag and lift force coefficients, respectively; Wref = Reference width = b" for C d , d" for C l ; pref = Reference pressure at measurement levels, as mentioned in Equation (1). Torsion (T) for all angles of wind incidence with respect to the origin wasevaluated using the measured pressures along with lever arms at each level.…”

Section: Coefficientsmentioning

confidence: 99%

Wind Tunnel Pressure Measurement Studies on a Tall Building With Elliptic Cross-Section: Effect of Angle of Wind Incidence

Afreen¹

2015

IJRET

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SynopsisWind tunnel pressure measurement studies were carried out on a rigid model (geometric scale 1:300) of a tall ellipticbuilding having minor axis of 100mm (b),major axis of 200mm (d) and height (h) of 700mm, under simulated open terrain in a Boundary Layer Wind Tunnel (BLWT) facility available at CSIR-SERC, Chennai. The measurement of pressures were made using 8 pressure sensors for 12 different angles of wind incidence, ""ranging between 0°(wind normal to minor axis)and 90°(wind normal to major axis). Based on the analysis, mean pressure coefficients, mean drag/lift force and torsion coefficients were obtained corresponding to reference pressures at the respective measurement levels. It is observed that the evaluated values of mean drag force coefficients increased with change in angles of wind incidence from 0° to 90°. The evaluated values of mean lift force coefficientsincreased with change in angles of wind incidence from 0° up to 40 and beyond which itdecreased. The evaluated values of meandrag forcecoefficients were compared with the values reported in Codes of Practice viz. IS: 875 (Part 3) and AS-NZS 1170.2. The evaluated values were found to be comparablewith the values reported in IS: 875for  = 90° and inAS-NZSfor  = 0°.

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“…The investigation of simple nonlinear FSI systems is an active one and recent experimental work has shown that a single degree of freedom pendular disk in a cross flow exhibits bistability (Obligado et al 2013). An entire field of literature exists on the rotational galloping and torsional flutter of bluff cylinders due to their prevalence in civil and industrial engineering (Nakamura 1990;Van Oudheusden 1996;Robertson et al 2003;Alonso et al 2010). Understandably these analyses are mostly focused on preventing such large amplitude motions and generally feature quasi-static analysis and static experiments at high Reynolds number.…”

Section: Introductionmentioning

confidence: 99%

Chaotic rotation of a towed elliptical cylinder

Weymouth

2014

J. Fluid Mech.

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In this paper I consider the self-excited rotation of an elliptical cylinder towed in a viscous fluid as a canonical model of nonlinear fluid structure interactions with possible applications in the design of sensors and energy extraction devices. First, the self-excited ellipse system is shown to be analogous to the forced bistable oscillators studied in classic chaos theory. A single variable, the distance between the pivot and the centroid, governs the system bifurcation into bi-stability. Next, fully coupled computational fluid dynamics simulations of the motion of the cylinder demonstrate limit cycle, period doubling, intermittently chaotic, and fully chaotic dynamics as the distance is further adjusted. The viscous wake behind the cylinder is presented for the limit cycle cases and new types of stable wakes are characterized for each. In contrast, a chaotic case demonstrates an independence of the wake and structural states. The rotational kinetic energy is quantified and correlated to the vortex shedding and the trajectory periodicity. Chaotic and high-period system responses are found to persist when structural damping is applied and for Reynolds numbers as low as 200.

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On the galloping instability of two-dimensional bodies having elliptical cross-sections

Cited by 45 publications

References 10 publications

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

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

Wind Tunnel Pressure Measurement Studies on a Tall Building With Elliptic Cross-Section: Effect of Angle of Wind Incidence

Chaotic rotation of a towed elliptical cylinder

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