Wind-induced response of light and slender arched structures in twin arrangement: Wind tunnel tests and full-scale monitoring

2019 ◽  
Vol 190 ◽  
pp. 262-275 ◽  
Author(s):  
Sara Muggiasca ◽  
Ilmas Bayati ◽  
Stefano Giappino ◽  
Lorenzo Rosa ◽  
Marco Belloli
2021 ◽  
pp. 136943322110339
Author(s):  
Jian Guo ◽  
Changliang Xiao ◽  
Jiantao Li

A hill with a lattice transmission tower presents complex wind field characteristics. The commonly used computational fluid dynamics (CFD) simulations are difficult to analyze the wind resistance and dynamic responses of the transmission tower due to structural complexity. In this study, wind tunnel tests and numerical simulations are conducted to analyze the wind field of the hill and the dynamic responses of the transmission tower built on it. The hill models with different slopes are investigated by wind tunnel tests to measure the wind field characteristics, such as mean speed and turbulence intensity. The study shows that the existence of a transmission tower reduces the wind speed on the leeward slope significantly but has little effect on the windward slope. To study the dynamic behavior of the transmission tower, a hybrid analysis procedure is used by introducing the measured experimental wind information to the finite element tower model established using ANSYS. The effects of hill slope on the maximum displacement response of the tower are studied. The results show that the maximum value of the response is the largest when the hill slope is 25° compared to those when hill slope is 15° and 35°. The results extend the knowledge concerning wind tunnel tests on hills of different terrain and provide a comprehensive understanding of the interactive effects between the hill and existing transmission tower regarding to the wind field characteristics and structural dynamic responses.


2017 ◽  
Vol 24 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Yang Su ◽  
Huoyue Xiang ◽  
Chen Fang ◽  
Lei Wang ◽  
Yongle Li

2021 ◽  
Vol 1201 (1) ◽  
pp. 012007
Author(s):  
I. Kusano ◽  
E. Cheynet ◽  
J. B. Jakobsen ◽  
J. Snæbjörnsson

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.


2021 ◽  
Author(s):  
Erwan Auburtin ◽  
Jang Kim ◽  
Hyunchul Jang ◽  
Lawrence Lai ◽  
Jason McConochie ◽  
...  

Abstract The Prelude Floating Liquefied Natural Gas (FLNG) facility is moored with an internal turret allowing it to perform offloading operations of liquefied natural and petroleum gas products. It does so in either a Free Weathervaning (FW) mode, i.e. by allowing the unit to rotate according to environmental loads, or in a Thruster-Assisted (TA) mode, i.e. by using the stern thrusters to maintain a fixed heading deemed preferable for the entire operation, or a particular phase. An accurate estimation of the various environment effects, in terms of forces on the FLNG and LNG carrier, is critical to ensure a correct prediction of its heading or the required thruster forces, depending on the selected operating mode. The predominant loads driving the weathervaning behavior are wind and current loads. These loads have been estimated from wind tunnel tests during the engineering phase. Since the Prelude FLNG has been installed on-site, field measurements have provided an opportunity for comparison and shown some differences with the numerical predictions based on the estimated loads, prompting a need for verification of current loads by an independent method. For the Prelude FLNG application, current loads play an important role due to facility size and significant tidal currents. It has been shown in some previous studies that wind tunnel tests for a model of under-water geometry may underestimate current loads compared to those on a full-scale vessel. There is a boundary layer along the wind tunnel floor in wind tunnel tests, while the current profile is relatively uniform over the hull draft in the real ocean condition. Moreover experimental tests present some additional drawbacks: they are performed at a reduced scale (1:225), the Reynolds number is lower than full-scale even with a large wind tunnel speed, and it is difficult to model the long (150m full-scale) Water Intake Risers (WIR) extending below the hull bottom. In order to investigate these effects, state-of-the-art full-scale CFD simulations were performed for the Prelude hull and WIR. The test program included different current speeds and directions, and several sensitivity studies: Reynolds number effect between model- and full-scales, effect of current speed profile (comparing uniform and boundary layer profiles at model scale), effect of FLNG rotation in yaw, impact of unsteady current, and presence of marine growth. Extreme dimensions of Prelude FLNG and requirements for accuracy of this study called for the CFD calculations to be performed on the High Performance Computing (HPC) clusters - Stampede2 and Frontera - at the Texas Advanced Computing Center (TACC), which are both amongst the world’s largest supercomputers. This paper describes the assumptions and challenges of the CFD study and discusses the results of the main program and various sensitivities. The main conclusions and lessons learnt are also discussed.


Author(s):  
Biagio Imperatore ◽  
Giulio Guj ◽  
Antonio Ragni ◽  
Antonio Pizzicaroli ◽  
Emanuele Giulietti

2018 ◽  
Vol 18 (12) ◽  
pp. 1850156
Author(s):  
Yi Zhou ◽  
Yuanqi Li ◽  
Akihito Yoshida

Flexible roof structures, such as membranes, are sensitive to wind action due to their flexibility and light weight. Previously, the effect of added mass on the vibration frequency of membrane structures has been experimentally tested. However, the effect of added mass on wind-induced vibration remains unclear. The purpose of this paper is to investigate the effect of added mass on the wind-induced vibration of a circular flat membrane based on wind tunnel tests. First, wind tunnel tests were conducted to obtain wind pressure distribution from the rigid model and wind-induced vibration from the aeroelastic model of a circular flat membrane. Secondly, a dynamic finite element analysis for the proposed added mass model was conducted to obtain the wind-induced vibration of the membrane structure. Then, with the wind pressure distribution obtained from the rigid model tests, dynamic analysis was conducted either with or without consideration of the effect of added mass. According to the dynamic analysis results and the wind tunnel test results, it is clear that considering the effect of added mass in dynamic analysis can significantly improve the accuracy of a wind-induced response. Such an effect is more significant at the windward than the central zone. The inclusion of added mass can result in a larger displacement response as wind velocity increases but a smaller response as the prestress level increases.


2012 ◽  
Vol 220-223 ◽  
pp. 771-774
Author(s):  
Yin Zhi He ◽  
Zhi Gang Yang

In this paper rear left side window buffeting characteristics of a production sedan under different yaw angles and different window opening sizes are investigated through full-scale aeroacoustic wind tunnel tests. By yaw angle -10 degree, as driver position on the lee side, the resonance peak SPL is much less than that by yaw angle 0 or +10 degree and the corresponding frequency is also some lower than that by yaw angle 0 or +10 degree. As window opening size turns small, the resonance peak SPL decreases. By side window with 25% opening size, the peak SPL is much less than that by side window with 50% or 100% opening size. In addition, the corresponding frequency is also some lower than that by side window with 50% or 100% opening size. Different test positions at the front row or back row show very similar buffeting characteristics.


2014 ◽  
Vol 59 (4) ◽  
pp. 1-12
Author(s):  
Reuben Raz ◽  
Aviv Rosen ◽  
Luigi S. Cicolani ◽  
Jeffery Lusardi

Previously, the authors showed that dynamic wind tunnel tests of a suspended CONEX cargo container model exhibited encouraging levels of success in predicting the stability characteristics and speed envelope of the full-scale load. The present study includes further use of the UH-60/CONEX system to investigate effects that were observed previously, but not fully addressed. These effects include the influence of pilot inputs and helicopter motions on the coupled pilot/helicopter/slung-load dynamics, the influence of center of gravity offset of the slung load, and the behavior of a load when a yaw swivel is not used in the suspension. It is shown that all three effects are important and affect the slung-load dynamics. The capability of wind tunnel tests to predict the behavior of slung loads in flight is shown for these effects.


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