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Aerodynamic stability evolution tendency of suspension bridges with spans from 1000 to 5000 m

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0980-z

摘要： Aerodynamic instability owing to aerostatic and flutter-related failures is a significant concern in the wind-resistant design of long-span suspension bridges. Based on the dynamic characteristics of suspension bridges with spans ranging from 888 to 1991 m, we proposed fitted equations for increasing spans and base frequencies. Finite element models of suspension bridges with increasing span from 1000 to 5000 m were constructed. The structural parameters were optimized to follow the fitted tendencies. To analyze the aerodynamic instability, streamlined single-box section (SBS), lattice truss section (LTS), narrow slotted section (NSS), and wide slotted section (WSS) were considered. We performed three-dimensional (3-D) full-mode flutter analysis and nonlinear aerostatic instability analysis. The flutter critical wind speed continuously decreases with span growth, showing an unlimited approaching phenomenon. Regarding aerostatic instability, the instability wind speed decreases with span to approximately 3000 m, and increases when the span is in the range of 3000 to 5000 m. Minimum aerostatic instability wind speed with SBS or LTS girder would be lower than observed maximal gust wind speed, indicating the probability of aerostatic instability. This study proposes that suspension bridge with span approximately 3000 m should be focused on both aerostatic instability and flutter, and more aerodynamic configuration optimistic optimizations for flutter are essential for super long-span suspension bridges with spans longer than 3000 m.

关键词： suspension bridge super long-span finite element model aerodynamic instability aerodynamic configuration

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Numerical analysis of aerodynamic noise radiated from cross flow fan

CHEN Anbang, LI Song, HUANG Dongtao

《能源前沿（英文）》 2008年第2卷第4期页码 443-447 doi: 10.1007/s11708-008-0063-9

摘要： The flow field in a cross flow fan was simulated by solving the 2-D unsteady Reynolds-averaged Navier-Stokes equations. The calculated pressure fluctuations of the blades, the vortex wall, and the rear wall were then used as noise sources to calculate the sound field. The Ffowcs Williams-Hawkings (FW-H) equation was employed to predict the noise field caused by these sources. The predictions show that the rear wall and the vortex wall sources contribute significantly to the total noise and that both the predicted aerodynamic performance and noise agree well with the experimental results.

关键词： predicted aerodynamic Williams-Hawkings calculated pressure aerodynamic performance unsteady Reynolds-averaged

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Combustion instability detection using the wavelet detail of pressure fluctuations

JI Junjie, LUO Yonghao

《能源前沿（英文）》 2008年第2卷第1期页码 116-120 doi: 10.1007/s11708-008-0019-0

摘要： A combustion instability detection method that uses the wavelet detail of combustion pressure fluctuations is put forward. To confirm this method, combustion pressure fluctuations in a stoker boiler are recorded at stable and unstable combustion with a pressure transducer. Daubechies one-order wavelet is chosen to obtain the wavelet details for comparison. It shows that the wavelet approximation indicates the general pressure change in the furnace, and the wavelet detail magnitude is consistent with the intensity of turbulence and combustion noise. The magnitude of the wavelet detail is nearly constant when the combustion is stable, however, it will fluctuate much when the combustion is unstable.

关键词： comparison wavelet approximation pressure transducer general pressure consistent

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海底不稳定性研究进展及展望

高伟健,李伟

《中国工程科学》 2023年第25卷第3期页码 109-121 doi: 10.15302/J-SSCAE-2023.03.010

摘要：

海底不稳定性及次生海底地质灾害广泛存在于海洋之中，对海岸港口设施、海洋钻井平台、海底管道光缆等海底基础建设颇具威胁。但目前对海底不稳定性的成因机制与主控因素仍知之甚少，为加深对海底不稳定性的认识，本文回顾了海底不稳定性研究进展，梳理了海底不稳定性及次生海底地质灾害的主要类别、全球分布情况和地球物理识别特征，归纳了目前海底不稳定性研究的定量分析方法，进一步分析了其成因机制、控制因素及工程地质灾害风险，探讨了海底陆坡失稳演化过程试验模拟技术的适用范畴与技术瓶颈。最后，从海底不稳定性的致灾机理研究、多源数据智能分析和海底失稳立体监测3 个维度提出了未来海底不稳定性研究的发展方向与对策建议，以期为海底不稳定性的模拟、预测和预警等工作提供指导性建议。

关键词：海底不稳定性；海底地质灾害；成因机制；风险评估；不稳定性分析

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Flutter control effect and mechanism of central-slotting for long-span bridges

YANG Yongxin, GE Yaojun, XIANG Haifan

《结构与土木工程前沿（英文）》 2007年第1卷第3期页码 298-304 doi: 10.1007/s11709-007-0039-6

摘要： The flutter control effect and mechanism of central-slotting, which have gradually been adopted in the design and construction of long-span bridges as an effective flutter controlling measure, were investigated with theoretical analysis and wind tunnel test. Five basic girder cross-sections representing five typical aerodynamic configurations were selected and central-slotted with two different slot widths. Then, a series of sectional model tests and theoretical analyses based on the two-dimensional three-degrees-of-freedom coupling flutter analysis method (2 dimension-3 degrees of freedom method, 2d-3DOF method) were carried out to investigate the aerodynamic performance, flutter mechanism and flutter modality of the five basic sections and their corresponding central-slotted sections. The results show that central-slotting can not always improve the aerodynamic stability of bridge structure. The control effect of central-slotting depends on the aerodynamic configuration of the original girder section and the corresponding central-slotting width. If the original section is inappropriate or the slot width is unsuitable, central-slotting will even deteriorate the structural flutter performance. Theoretical investigations indicated that the differences in flutter control effects come from the different formation and evolution of aerodynamic damping, and flutter modality especially the participation level of heaving motion also has a significant influence on the control effect of central-slotting.

关键词： aerodynamic configuration aerodynamic performance flutter mechanism aerodynamic stability theoretical analysis

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Experimental study of aerodynamic interference effects on aerostatic coefficients of twin deck bridges

Zhiwen LIU , Zhengqing CHEN , Gao LIU , Xinpeng SHAO ,

《结构与土木工程前沿（英文）》 2009年第3卷第3期页码 292-298 doi: 10.1007/s11709-009-0048-8

摘要： The aerodynamic interference effects on aerostatic coefficients of twin deck bridges with large span were investigated in detail by means of wind tunnel test. The distances between the twin decks and wind attack angles were changed during the wind tunnel test to study the effects on aerodynamic interferences of aerostatic coefficients of twin decks. The research results have shown that the drag coefficients of the leeward deck are much smaller than that of a single leeward deck. The drag coefficients of a windward deck decrease slightly compared with that of a single deck. The lift and torque coefficients of windward and leeward decks are also affected slightly by the aerodynamic interference of twin decks. And the aerodynamic interference effects on lift and torque coefficients of twin decks can be neglected.

关键词： twin decks aerodynamic interference effects aerostatic coefficients wind tunnel test

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New response surface model and its applications in aerodynamic optimization of axial compressor blade

LIU Xiaojia, NING Fangfei

《能源前沿（英文）》 2008年第2卷第4期页码 541-549 doi: 10.1007/s11708-008-0077-3

摘要： A parametric method for the axial compressor 2D blade profiles is proposed in which the blade geometries are defined with the parameters commonly used for blade definition, which ensures that the geometric significance is clear and an unreasonable blade profile is not generated. Several illustrations are presented to show the fitting precision of the method. A novel response surface model is proposed which regards the objective distribution function in the vicinity of a sample as normal school, and then generates the response surface function in the whole design space by a linear combination of distribution functions of all the samples. Based on this model, a numerical aerodynamic optimization platform for the axial compressor 2D blade profiles is developed, by which aerodynamic optimization of two compressor blade profiles are presented.

关键词： definition objective distribution fitting precision combination numerical aerodynamic

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Aerodynamic interference effects and mitigation measures on vortex-induced vibrations of two adjacent

Xiaoliang MENG, Ledong ZHU, Zhenshan GUO

《结构与土木工程前沿（英文）》 2011年第5卷第4期页码 510-517 doi: 10.1007/s11709-011-0129-3

摘要： By examining the two neighboring Haihe Bridges with semi- and full-closed bridge decks, the aerodynamic interference between the two decks on the vortex-induced vibration (VIV) and the corresponding aerodynamic mitigation measures are investigated via a series of wind tunnel tests with a spring-suspended sectional model aided with computational fluid dynamics (CFD) method. The results show that the VIV responses of both bridges can be significantly affected by the aerodynamic interference and that the extent of the influence varies with the shapes of the windward and leeward decks. The VIV amplitudes of the windward bridge are often fairly close to those of the single bridge. However, those of the leeward bridge are magnified substantially by aerodynamic interference if the same structural and aerodynamic configurations are adopted for the two bridges. Otherwise, the VIV responses are not significantly increased and may even be reduced by the aerodynamic interference if different configurations are employed for the two bridges. Furthermore, an effective combined measure of adding wind barriers and sharpening the wind fairing noses of the two box decks is presented for mitigating both the vertical and torsional VIV responses of the windward and leeward bridges.

关键词： separated parallel decks vortex-induced vibration aerodynamic interference aerodynamic mitigation measure semi-closed box deck full-closed box deck

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Aerodynamic impact of train-induced wind on a moving motor-van

Jiajun HE; Huoyue XIANG; Yongle LI; Bin HAN

《结构与土木工程前沿（英文）》 2022年第16卷第7期页码 909-927 doi: 10.1007/s11709-022-0833-1

摘要： The newly-built single-level rail-cum-road bridge brings the issue of the aerodynamic impact of train-induced wind on road automobiles. This research introduced a validated computational fluid dynamics (CFD) model regarding this concern. Such an aerodynamic impact mechanism was explored; a relationship between the transverse distance between train and motor-van (hereinfafter referred to as van) and the aerodynamic effects on the van was explored to help the optimization of bridge decks, and the relationship between the automobile speed and aerodynamic variations of a van was fitted to help traffic control. The fitting results are accurate enough for further research. It is noted that the relative speed of the two automobiles is not the only factor that influences the aerodynamic variations of the van, even at a confirmed relative velocity, the aerodynamic variations of the van vary a lot as the velocity proportion changes, and the most unfavorable case shows an increase of over 40% on the aerodynamic variations compared to the standard case. The decay of the aerodynamic effects shows that not all the velocity terms would enhance the aerodynamic variations; the coupled velocity term constrains the variation amplitude of moments and decreases the total amplitude by 20%–40%.

关键词： rail-cum-road bridge aerodynamic impact train-induced wind CFD aerodynamic force quantitative analysis fitting

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表面张力作用下柱形胶体的弹性失稳

黄殿武,乔玲,汪时机

《中国工程科学》 2007年第9卷第4期页码 50-54

摘要：

采用弹性理论研究了圆柱形胶体在表面张力作用下的弹性失稳问题；利用能量泛函变分的方法导出了发生弹性失稳的非经典边界条件，得到了失稳的判据方程。分析判据方程发现，弹性失稳与圆柱体的半径、内禀尺度和失稳波长相关。

关键词：柱形胶体弹性失稳内禀尺度表面效应

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工程饱和介质中漩涡光的调制不稳定性 Review

D.G. Pires, N.M. Litchinitser

《工程（英文）》 2022年第17卷第10期页码 31-43 doi: 10.1016/j.eng.2022.04.022

摘要：

光束在水下环境、雾、云或生物组织等混浊介质中的传播在科学和技术中有着越来越重要的应用，包括生物成像、水下和自由空间通信技术。虽然这些应用在传统上依赖于常规的线性偏振高斯光束，但光具有许多未被发掘的自由度，如自旋角动量（SAM）和轨道角动量（OAM）。本文提出了具有“旋转”自由度的复杂光束在工程化非线性胶体介质中的非线性光-物质相互作用。利用变分法和摄动法，我们考虑了非圆柱光学涡旋、椭圆光学涡旋和高阶贝塞尔光束在时间上的积分（HOBBIT），来预测这些光束演化的动力学行为和稳定性。这些结果可应用于许多强散射环境下涉及光透射的情况。

关键词： Optical vortex Orbital angular momentum Modulation instability Turbid media

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Numerical investigation of aerodynamic performance influenced by circumferentially pre-swirling coming

WANG Qikun, CHEN Kangmin

《能源前沿（英文）》 2007年第1卷第4期页码 435-440 doi: 10.1007/s11708-007-0063-5

摘要： Numerical investigation is implemented on aerodynamic performance inside the crossover and de-swirling cascade of a multistage centrifugal compressor. The emphasis is put on the aerodynamic performance influenced by the circumferent

关键词： aerodynamic investigation centrifugal de-swirling circumferent

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Improvement of aerodynamic stability of suspension bridges with H-shaped simplified stiffening girder

Hiroshi KATSUCHI,Hitoshi YAMADA,Mayuko NISHIO,Yoko OKAZAKI

《结构与土木工程前沿（英文）》 2016年第10卷第1期页码 93-102 doi: 10.1007/s11709-015-0311-0

摘要： Wind-tunnel study on the improvement of aerodynamic stability of simplified suspension-bridge girder structures was conducted with using a 1/40-scaled section model. Objective of the study is the development of an economically superior suspension bridge with 500–1,000 m center span length. The wind-tunnel test showed that an edge-girder type cross section exhibited large amplitude torsional vortex-induced vibration as well as torsional flutter at a low wind speed. Accordingly, aerodynamic countermeasures of open grating deck and triangular faring, and structural countermeasures of center stay, diagonal bracing and mass increase were tried to improve the aerodynamic stability. Finally, feasibility of the best combination to a full-scale bridge was examined by structural analysis.

关键词： suspension bridge aerodynamics simplified girder wind-tunnel test

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Parametric oscillation of cables and aerodynamic effect

Yong XIA, Jing ZHANG, Youlin XU, Yozo FUJINO,

《结构与土木工程前沿（英文）》 2010年第4卷第3期页码 321-325 doi: 10.1007/s11709-010-0028-z

摘要： This paper addresses the aerodynamic effect on the nonlinear oscillation, particularly parametric vibration of cables in cable-stayed bridges. A simplified 2-DOF model, including a beam and a stayed cable, is formulated first. Response of the cable under global harmonic excitation which is associated with wind speed is obtained using the multiple scales method. Via numerical analysis, the stability condition of the cable in terms of wind speed is derived. The method is applied to a numerical example and a long-span bridge to analyze its all stay cables. It is demonstrated that very large vibration at one of the longest cables in the middle span of the bridge can be parametrically excited when the wind speed is over around 210 km/h (58.5 m/s).

关键词： parametric vibration cables cable-stayed bridge nonlinear vibration

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Underlying mechanism of the hydrothermal instability of Cu

Nadeen Al-Janabi,Abdullatif Alfutimie,Flor R. Siperstein,Xiaolei Fan

《化学科学与工程前沿（英文）》 2016年第10卷第1期页码 103-107 doi: 10.1007/s11705-015-1552-0

摘要： Water induced decomposition of Cu (BTC) (BTC= benzene-1,3,5-tricarboxylate) metal-organic framework (MOF) was studied using dynamic water vapour adsorption. Small-angle X-ray scattering, Fourier transform infrared spectroscopy and differential scanning calorimetry analyses revealed that the underlying mechanism of Cu (BTC) MOF decomposition under humid streams is the interpenetration of water molecules into Cu-BTC coordination to displace organic linkers (BTC) from Cu centres.

关键词： hydrothermal stability metal-organic framework (MOF) open metal sites (OMSs) dynamic water vapour adsorption