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Dynamic Response of Sea-Crossing Rail-cum-Road Cable-Stayed Bridge Influenced by Random Wind–Wave–undercurrent Coupling

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China Ocean Engineering 2023年第1期37卷 85-100页

作者： BIAN Chen-jie DU Li-ming WANG Ga-ping LI Xin LI Wei-ran School of Civil Engineering Dalian Jiaotong UniversityDalian 116028China School of Locomotive and Rolling stock Engineering Dalian Jiaotong UniversityDalian 116028China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

Sea-crossing bridges are affected by random wind–wave–undercurrent coupling loads, due to the complex marine environment. The dynamic response of long-span Rail-cum-Road cable-stayed bridges is particularly severe under their influence, potentially leading to safety problems. In this paper, a fluid–structure separation solution method is implemented using Ansys–Midas co-simulation, in order to solve the above issues effectively while using less computational resources. The feasibility of the method is verified by comparing the tower top displacement response with relevant experimental data. From time and frequency domain perspectives, the displacement and acceleration responses of the sea-crossing Rail-cum-Road cable-stayed bridge influenced by wave-only, wind–wave, and wind–wave–undercurrent coupling are comparatively studied. The results indicate that the displacement and acceleration of the front bearing platform top are more significant than those of the rear bearing platform. The dominant frequency under wind–wave–undercurrent coupling is close to the natural vibration frequencies of several bridge modes,such that wind–wave–undercurrent coupling is more likely to cause a resonance effect in the bridge. Compared with the wave-only and wind–wave coupling, wind–wave–undercurrent coupling can excite bridges to produce larger displacement and acceleration responses: at the middle of the main girder span, compared with the wave-only case, the maximum displacement in the transverse bridge direction increases by 23.58% and 46.95% in the wind–wave and wind–wave–undercurrent coupling cases, respectively;at the tower top, the variation in the amplitude of the displacement and acceleration responses of wind–wave and wind–wave–undercurrent coupling are larger than those in the wave-only case, where the acceleration change amplitude of the tower top is from-0.93 to 0.86 m/s^(2) in the waveonly case, from-2.2 to 2.1 m/s^(2) under wind–wave coupling effect, and from-2.6 to 2.6

关键词： random wind wave undercurrent coupling effect Rail-cum-Road cable-stayed bridge dynamic response

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Relationship between a function of the northward pressure gradient and the Pacific Equatorial undercurrent

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Acta Oceanologica Sinica 2018年第9期37卷 22-28页

作者： CHEN Xuan ZHENG Chongwei WU Hui YOU Xiaobao LI Xunqiang WANG Huipeng The 75839 Army People's Liberation Army Guangzhou 510510 China State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics the Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Beijing Institute of Applied Meteorology Beijing 100029 China College of Meteorology and Oceanography National University of Defense Technology Nanjing 211101 China

The Equatorial undercurrent（EUC） plays an important role in ocean circulation and global climate change. Near the equator, as the Coriolis parameter goes to 0, equatorial currents cannot be described by geostrophy in which the pressure gradient force term is balanced by the Coriolis force term. Many previous studies focus on the relationships between the EUC and El Ni？o-Southern Oscillation（ENSO）, the thermocline, sea surface topography, the distribution of equatorial wind stress and other atmosphere-ocean factors. However, little attention has been paid to the northward pressure gradient（NGT）, which may also be important to the EUC. The pressure can be regarded as a complex nonlinear function of terms including temperature, salinity and *** study attempts to reveal the connection between a function of the northward pressure gradient（FNP） and the EUC. The connection is derived from primitive equations, by simplifying the equations with using scaling analysis, and shows that the beta effect may be the main reason why the FNP is important to the EUC. The vertical structure of the EUC can be partially described by the FNP. The NGT has an obvious influence on the EUC while the eastward pressure gradient has a relatively smaller effect.

关键词： Equatorial undercurrent northward pressure gradient beta effect

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DYNAMIC AND THERMOHALINE PROPERTIES OF THE MINDANAO undercurrent,PART Ⅱ: THERMOHALINE STRUCTURE

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Chinese Journal of Oceanology and Limnology 1998年第3期16卷 206-213页

作者：王凡胡敦欣 Institute of Oceanology Chinese Academy of Sciences Qingdao

Hydrographic data from eleven 1986 - 1991 cruises at zonal sections near 8°N from the Philippine coast to 130°E were used to examine thermohaline smictim and waer mass properties of the western boundary cnrrents there, especially those of the Mindanao Underconnt (MUC). The finding that the MLC consisted of two water masses with salinity of M.6 at 26.9 σt and 34.52 at 27. 2 σt which were remnants of the lower part of the southern Pacific Subtropical Waer (SPSW) and of the Antarctic Intermediate Water (AAIW) of South Pacific origin, respectively, showed that the MUC was not a local transient but originaed elsewhere. As the MUC flowed from 7 .5°N to 8°N, part of it carrying the SPSW turns anticyclonically and eastward. The Northem Pacilic Intermediate Watr (NPIW) often joins the MUC, which suggests that the NPIW carried by the MC partly to northward as a result of the shear between the MC and the MUC or other proceesses. The shear instability provides the energy for the irregular fluctuation of the MUC.

关键词： Mindanao undercurrent (MUC) thermohaline structure Antarctic Intermediate Water Southern Pacific Subtropical Water Northern Pacific Intermediate Water

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Homotopic Mapping Solving Method for Perturbed Mechanism of Western Boundary undercurrents in Equator Pacific

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Chinese Geographical Science 2006年第4期16卷 347-350页

作者： MO Jiaqi WANG Hui LIN Wantao Department of Mathematics Anhui Normal University Wuhu 241000 China Division of Computational Science E-Instilutes of Shanghai Universities Shanghai Jiaotong University Shanghai 200240 China Department of Mathematics Huzhou Teachers College Huzhou 313000 China Chinese Academy of Meteorological Sciences Beijing 100081 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The perturbed boundary undercurrent is an exceptional event in the tropical atmosphere and ocean. It is a complicated nonlinear system. Its appearance badly affects not only natural conditions such as climate and environment, but also global economic development and human living, and brings about many calamities. Thus there is very attractive study on its rules in the international academic circles. Many scholars made more studies on its local and whole behaviors using different methods, such as self-anamnestic principle, Fokker-Plank Equation method, higher order singular pedigree and predictable study, rapid change on boundary, indeterminate adaptive control, multi-eogradient method and so on. Nonlinear perturbed theory and approximate method are very attractive studies in the international academic circles. Many scholars considered a class of nonlinear problems for the ordinary differential equation, the reaction diffusion equations, the boundary value of elliptic equation, the initial boundary value of hyperbolic equation, the shock layer solution of nonlinear equation and so on. In this paper, a class of perturbed mechanism for the western boundary undercurrents in the equator Pacific is considered. Under suitable conditions, using a homotopic mapping theory and method, we obtain a simple and rapid arbitrary order approximate solution for the corresponding nonlinear system. For example, a special case shows that using the homotopic mapping method, there is a high accuracy for the computed value. It is also provided from the results that the solution for homotopic mapping solving method can be used for analyzing operator for perturbed mechanism of western boundary undercurrents in the equator Pacific.

关键词： undercurrent perturbation approximate solution equator Pacific

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Structure and Temporal Variability of Mediterranean Water in Hydrological and Marine Seismic Data South of Portimao Canyon (Gulf of Cadiz), from 1999 to 2002

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International Journal of Geosciences 2011年第3期2卷 185-194页

作者： Elise Quentel Xavier Carton Marc Andre Gutscher 不详

Hydrological and marine seismic data, collected in the Gulf of Cadiz (respectively in July 1999, 2000, 2001 and 2002, and in April 2000 and 2001) are analysed to reveal the various structures of Mediterranean Water (MW). Both the hydrological and seismic data clearly identify the MW undercurrents on the Iberian slope, detached MW eddies (meddies and a cyclone) and smaller fragments of MW (filaments and small eddies). Seismic reflectivity and synthetic reflectivity computed from hydrology, indicate that strong acoustic reflectors, associated with 8 - 64 m thick homogeneous water layers, are found above and below meddies and filaments, around the MW undercurrents, but mostly in the lower part of cyclones and below submesoscale eddies. Reflectors are also observed in the near surface layers where thermohaline contrasts are quite pronounced. The successful use of seismic data to locate submesoscale MW structures, superior to that of hydrology, is related to the improved horizontal resolution.

关键词： Mediterranean Water Eddies undercurrent Layering Hydrological Data Seismic Reflectivity Submesoscale Structures

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