Galloping instabilities of two-dimensional triangular cross-section bodies

Alonso, G.; Meseguer, José; Pérez-Grande, Isabel

doi:10.1007/s00348-005-0974-8

Cited by 69 publications

(60 citation statements)

References 21 publications

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“…The results of the dynamic tests show that the region of unstable configurations in the  versus  plane is smaller than the one obtained when the static Den Hartog criterion is applied, as one could expect taking into account previous results concerning the galloping behaviour of triangular crosssection bodies published elsewhere [12] For this type of H sections, a noticeable effect of the stream turbulence has been found. In this sense, the turbulence effect on the analysed H section bodies seems to behave in a similar way as in rectangular section bodies.…”

Section: Discussionsupporting

confidence: 52%

Influence of aerodynamic characteristics of H beams on galloping stability

Meseguer¹,

Sanz²

2014

IABSE Reports

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SummaryThis paper presents the experimental study developed on a prismatic beam with "H" section, sometimes used in bridges as suspenders, vertical bars or decks.The purpose of this study is to understand the physical behavior of the air around this type of section, in order to reduce the aerodynamic loads, the onset speed of galloping and even to avoid it. To achieve this, a study of the influence of all geometric parameters that define the section has been developed. Previously, the most interesting configurations have been selected using a smoke flow visualization technique in the wind-tunnel, then the corresponding static aerodynamic loads were measured, completed with dynamic tests and, finally, the parameters governing the phenomenon of galloping determined.

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Section: Discussionsupporting

confidence: 52%

Influence of aerodynamic characteristics of H beams on galloping stability

Meseguer¹,

Sanz²

2014

IABSE Reports

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“…However, most of those efforts have been focused on bodies with square or rectangular cross-sections, although prismatic bodies with other also interesting cross-sectional shapes can be unstable to transverse galloping (Blevins, 2001). A general analysis based on Glauert-Den Hartog criterion of two-dimensional triangular crosssectional bodies (the main vertex angle ft ranging from 10° to 90°) can be found in Alonso and Meseguer (2006), and a similar study but based on dynamical tests is reported in Alonso et al (2005Alonso et al ( , 2007, although these last studies are limited to the range 10°<^<60°.…”

Section: )mentioning

confidence: 91%

“…To asses the suitability of the static tests approach to support galloping analyses, both static and dynamic wind tunnel tests were performed (Alonso et al, 2005(Alonso et al, , 2007 showing that the results obtained from the static tests are in very good agreement with the dynamic ones. In the last decades large efforts have been devoted to experimentally study the galloping features of many bodies having different cross-sections.…”

Section: )mentioning

confidence: 99%

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

Alonso

Meseguer

Sanz-Andrés

et al. 2010

Journal of Wind Engineering and Industrial Aerodynamics

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Keywords:Galloping Elliptical cross-section bodies Wind tunnel Galloping, also known as Den Hartog instability, is the large amplitude, low frequency oscillation of a structure in the direction transverse to the mean wind direction. It normally appears in the case of bodies with small stiffness and structural damping, when they are placed in a flow provided the incident velocity is high enough. Galloping depends on the slope of the lift coefficient versus angle of attack curve, which must be negative. Generally speaking this implies that the body is stalled after boundary layer separation, which, as it is known in non-wedged bodies, is a Reynolds number dependent phenomenon. Wind tunnel experiments have been conducted aiming at establishing the characteristics of the galloping motion of elliptical cross-section bodies when subjected to a uniform flow, the angles of attack ranging from 0° to 90°. The results have been summarized in stability maps, both in the angle of attack versus relative thickness and in the angle of attack versus Reynolds number planes, where galloping instability regions are identified.

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“…The influence of relevant parameters like the incident turbulence (Novak and Tanaka, 1974;Li et al, 1998;Ziller andRuscheweyh, 1997, Hemon et al, 2001;Hemon and Santi, 2002), the geometry of the cross section (Ruecheweyh et al, 1996;Kawai, 1998;Luo et al, 1998;Gjelstrup and Georgakis, 2011), the Reynolds number (Sen and Mittal, 2011;Joly et al, 2012) or the hysteresis phenomenon (Parkinson and Brooks, 1961;Parkinson and Smith,1964;Luo et al, 2003;Ng et al, 2005, Vio et al, 2007Barrero-Gil et al, 2009;Dunnmon et al, 2011) have been treated. Although most of the effort in galloping research has been concentrated in bodies with square or rectangular cross-sections, prismatic bodies with other cross-sectional shapes have been also considered (Blevins, 1990;Naudascher and Rockwell, 1994;Alonso and Meseguer, 2006;Alonso et al, 2005Alonso et al, , 2007Alonso et al, , 2009Alonso et al, , 2010.…”

Section: Introductionmentioning

confidence: 99%

“…1) when subjected to cross-flow translational galloping vibration has been analysed through wind tunnel experiments. Triangular cross-section bodies have been chosen because these bodies have been extensively studied in the past (Alonso and Meseguer, 2006;Alonso et al, 2005Alonso et al, , 2007lungo and Buresti, 2009), so that a large amount of information is now available. In order to clarify the influence of the geometry on the hysteresis, six different triangular cross-sections have been considered, so that the hysteresis map in the angle of attack, triangle main vertex angle (a, /?…”

Section: Introductionmentioning

confidence: 99%

Hysteresis phenomena in transverse galloping of triangular cross-section bodies

Alonso

Lobera

Meseguer

2012

Journal of Fluids and Structures

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Transverse galloping is a type of aeroelastic instability characterised by large amplitude, low frequency oscillation of a structure in the direction normal to the mean wind direction. It normally appears in bodies with small stiffness and structural damping, provided the incident flow velocity is high enough. In the simplest approach transverse galloping can be considered as a one-degree-of-freedom oscillator subjected to aerodynamic forces, which in turn can be described by using a quasi-steady description. In this frame it has been demonstrated that hysteresis phenomena in transverse galloping is related to the existence of inflection points in the curve giving the dependence with the angle of attack of the aerodynamic coefficient normal to the incident flow. Aiming at experimentally checking such a relationship between these inflection points and hysteresis, wind tunnel experiments have been conducted. Experiments have been restricted to isosceles triangular cross-section bodies, whose galloping behaviour is well documented. Experimental results show that, according to theoretical predictions, hysteresis takes place at the angles of attack where there are inflection points in the lift coefficient curve, provided that the body is prone to gallop at these angles of attack.

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Galloping instabilities of two-dimensional triangular cross-section bodies

Cited by 69 publications

References 21 publications

Influence of aerodynamic characteristics of H beams on galloping stability

Influence of aerodynamic characteristics of H beams on galloping stability

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

Hysteresis phenomena in transverse galloping of triangular cross-section bodies

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