Separation Control on a Bridge Box Girder Using a Bypass Passive Jet Flow

Zhang, Liangquan; Chen, Guan-Bin; Chen, Wenli; Gao, Donglai

doi:10.3390/app7060501

Cited by 17 publications

(6 citation statements)

References 30 publications

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“…Therefore, the box girder of the bridge is designed as near streamline for alleviating the VIV. Due to the box girder being not entirely streamlined, the VIV often happens when the airflow velocity attains a specific value, i.e., the wake vortex frequency is equal to that of the box girder at this velocity [2,9]. In addition, the affiliate parts (i.e., railing, maintenance track, and streetlamps) that are set in the box girder also can affect the characteristics of the main girder and the fluctuation of the aerodynamic force.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation and Validation on Suppressing the Unsteady Aerodynamic Force and Flow Structure of Single Box Girder by Trailing Edge Jets

Chen

2022

Applied Sciences

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In the present investigation, a wind tunnel experiment was performed to evaluate the effectiveness of the trailing edge jets control scheme to mitigate the unsteady aerodynamic force and flow structure of a single box girder (SBG) model. The flow control scheme uses four isolated circular holes for forming the jet flow to modify the periodic vortex shedding behind the SBG model and then alleviate the fluctuation of the aerodynamic force acting on the test model. The Reynolds number is calculated as 2.08 × 104 based on the incoming velocity and the height of the test model. A digital pressure measurement system was utilized to obtain and record the surface pressure that was distributed around the SBG model. The surface pressure results show that the fluctuating amplitude of the aerodynamic forces was attenuated in the controlled case at a specific range of the non-dimensional jet momentum coefficient. The Strouhal number of the controlled case also deviates from that of the original SBG model. Except for the pressure measurement experiment, a high-resolution digital particle image velocimetry system was applied to investigate the detailed flow structure behind the SBG model to uncover the unsteady vortex motion process from the SBG model with and without the trailing edge jets flow control. As the jet flow blows into the wake, the alternating vortex shedding mode is switched into a symmetrical shedding mode and the width of the wake flow is narrowed. The proper orthogonal decomposition was used to identify the energy of the different modes and obtain its corresponding flow structures. Moreover, the linear stability analysis of the flow field behind the SBG model shows that the scheme of trailing edge jets can dramatically suppress the area of unsteady flow.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigation and Validation on Suppressing the Unsteady Aerodynamic Force and Flow Structure of Single Box Girder by Trailing Edge Jets

Chen

2022

Applied Sciences

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“…A large number of studies have shown that a sudden change in wind speed near the bridge pylon is unfavorable for driving stability [18], and countermeasures have been explored for improving the wind environment at the bridge deck and ensuring driving safety [19,20]. Wind barriers, as an effective countermeasure, have had increasing attention from scholars [21][22][23]. Alonso-Estebanez et al [24] numerically studied and compared the aerodynamic coefficients of a truck on an embankment both with and without the wind fences installed.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of the Wind Environment above Bridge Deck near the Pylon Zone and Wind Barrier Arrangement Criteria

et al. 2020

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Due to the complex arrangement of structural components in the vicinity of bridge pylon zones, the wind environment above bridge decks is very complicated. A sudden change in wind speed exerts an adverse effect on vehicle control stability. In order to investigate the characteristics of the flow field in the vicinity of the bridge pylon, the wind environment near an inverted Y-shaped pylon is studied by experimental and numerical methods. From the flow visualization and the wind speed measurement in the wind tunnel and the numerical simulation created using Fluent software, specific patterns of the direction and magnitude of wind speed at a range of vehicle height above the bridge deck near the pylon zone were observed along the longitudinal direction. This distribution pattern of the wind environment can effectively guide the wind barrier arrangement near the bridge pylon zone. Combined with the two safety evaluation indicators proposed in this paper, the optimal arrangement scheme of wind barriers in the bridge pylon zone of Sutong Bridge is determined. This paper deepens the understanding of the wind environment near the pylon zone and proposes an evaluation method for the wind environment near the pylon zone, which can serve as the basis for wind barrier arrangement in similar research projects.

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“…Zhang ve arkadaşları [7] tabliyenin alt yüzeylerine açtıkları deliklerden akış emme işlemi gerçekleştirilmesinin tabliye art izindeki girdapları bastırdığını ve bunun sonucu olarak salınımların azaltıldığını ve sürüklenme katsayısının kontrol yöntemi uygulanmadığı durum ile kıyaslandığında %75 oranında azaldığını yaptıkları sayısal çalışma ile göstermişledir. Zhang ve arkadaşları [8] Bu çalışmada, ikiz tabliyeler arasındaki akışın, iki tabliye arasına yerleştirilen ve tabliyelere paralel uzanan dairesel kesitli çubuk ile kontrolü hedeflenmiştir. Tabliyeler arasındaki mesafenin tabliye yüksekliğine oranı L/H=1,7 ve dairesel kesitli çubuk çapının tabliye yüksekliğine oranı D/H=0,11 seçilmiştir.…”

Section: Introductionunclassified

“…Zhang ve arkadaşları [7] tabliyenin alt yüzeylerine açtıkları deliklerden akış emme işlemi gerçekleştirilmesinin tabliye art izindeki girdapları bastırdığını ve bunun sonucu olarak salınımların azaltıldığını ve sürüklenme katsayısının kontrol yöntemi uygulanmadığı durum ile kıyaslandığında %75 oranında azaldığını yaptıkları sayısal çalışma ile göstermişledir. Zhang ve arkadaşları [8] [15] tabliyeler arasındaki mesafenin tabliye yüksekliğine oranının, L/H=1.7 değerinde yaptıkları deneysel çalışma ile tabliyelerin belirli aralıkla birbirlerine kiriş ve çapraz çubuklar ile bağlandığında girdap kaynaklı titreşimlerin tamamen bastırıldığını göstermişlerdir. Ma ve arkadaşları [16] tabliyeler arasına yerleştirdikleri gözenekli plakların akış kontrolü üzerine etkisini deneysel çalışma ile araştırmışlardır.…”

Section: Introductionunclassified

İkiz Tabliyeler Arasındaki Akışın Dairesel Kesitli Çubuk ile Kontrol Edilmesi

Durhasan

2019

Çukurova Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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ÖzBu çalışmada, uzun açıklıklı ikiz tabliyeler arasındaki akışın dairesel kesitli çubuk ile kontrol edilmesi hedeflenmiştir. İki tabliye arasındaki mesafenin tabliye yüksekliğine oranı L/H=1,7 ve dairesel kesitli çubuğun çapı 4 mm seçilmiştir. Deneyler Reynolds sayısının Re=23440 değerinde PIV tekniği kullanılarak gerçekleştirilmiştir. Dairesel kesitli çubuk iki tabliye arasında yatay yönde beş farklı ve dikey yönde üç farklı olmak üzere toplam on beş farklı noktada konumlandırılmıştır. PIV ölçüm sonuçları, dairesel kesitli çubuğun konumlandırıldığı yere bağlı olarak tabliyeler arasındaki ters akış bölgelerini önemli ölçüde etkilediğini ortaya koymuştur. Ayrıca, dairesel kesitli çubuğun iki tabliye arasındaki alt ve üst kayma tabakalarının etkileşimini azalttığı gözlemlenmiştir. Kontrol elamanın bulunmadığı durum için elde edilen Reynolds kayma gerilmesinin maksimum değeri, dairesel kesitli çubuğun tabliyeler arasında x/D=12,5 ve y/D=0'da konumlandırıldığında durum ile kıyaslandığında %49 oranında azalmıştır. AbstractIn this study, it was aim to flow control in the gap where between twin box girder by rod. The gap ratio of twin box girders and diameter of rod were selected as L/H=1.7 and 4 mm. Experiments were performed using PIV technique at Re=23440. The rod was located in the gap of twin box girders at fifteen different position (five different horizontal direction and three different vertical direction). The results of PIV measurements exhibited that the rod affected significantly reverse flow regions depends on the location. Also, the rod reduced interaction of shear layers on the upper and lower side in the gap. The peak maximum of Reynolds shear stress was decreased by 49% at x/D=12.5 and y/D=0 compared to without rod case.

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Separation Control on a Bridge Box Girder Using a Bypass Passive Jet Flow

Cited by 17 publications

References 30 publications

Experimental Investigation and Validation on Suppressing the Unsteady Aerodynamic Force and Flow Structure of Single Box Girder by Trailing Edge Jets

Experimental Investigation and Validation on Suppressing the Unsteady Aerodynamic Force and Flow Structure of Single Box Girder by Trailing Edge Jets

Characteristics of the Wind Environment above Bridge Deck near the Pylon Zone and Wind Barrier Arrangement Criteria

İkiz Tabliyeler Arasındaki Akışın Dairesel Kesitli Çubuk ile Kontrol Edilmesi

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