Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains,involving static aerodynamic forces and vortex-induced vibrations(VIVs).Static and dynamic sectiona...Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains,involving static aerodynamic forces and vortex-induced vibrations(VIVs).Static and dynamic sectional models of the girder and trains were employed for aerodynamic force measurement and VIV test,respectively.Results indicate that the aerodynamic interference effect on static aerodynamic forces of both the girder and trains is remarkable.When a single train exists,the horizontal position of the train has a small effect on aerodynamic coefficients of the girder.When two trains meet on the girder,the drag coefficient of the girder is significantly reduced compared with that of without train or with a single train;besides,during the whole meeting process,aerodynamic forces of the leeward train first drop and then increase suddenly.The fluctuation of aerodynamic force could cause redundant vibration of the train,which is unfavorable for safety and comfort.A train on the girder could worsen the girder VIV performance:a new vertical VIV appears in the triple-box girder when a train is on the girder,and the torsional VIV amplitude increases significantly when the train is on the windward side.展开更多
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...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.展开更多
The aerodynamic interference effects on aero-static 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 angle...The aerodynamic interference effects on aero-static 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 com-pared 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.展开更多
The correction method uses the static pressures measured near the tunnelwalls during model tests as boundary conditions. It is required that the flow near thewalls is subsonic and the freestream Mach number is less th...The correction method uses the static pressures measured near the tunnelwalls during model tests as boundary conditions. It is required that the flow near thewalls is subsonic and the freestream Mach number is less than 1. It is still valid whenthere are shock waves and supersonic pockets near the model as long as shock waves donot extend to walls, and the method is applicable to various ventilated wall or solid walltest sections. Corrections for three models tested abroad are in quite good agreementwith NASA's results, which are obtained by a nonhnear correction method. Thepresnet method has been apphed to B737 inodel tcsted in CARDC 1.2 m wind tunnel.The results show that this method is suitable for transonic wall interference correctionfor high aspect ratio airplane tests.展开更多
To promote and develop the theoretical basis and application of the wind-vehicle-bridge coupling vibration system,the corresponding research status and prospects are reviewed and discussed from five aspects,i.e.,the a...To promote and develop the theoretical basis and application of the wind-vehicle-bridge coupling vibration system,the corresponding research status and prospects are reviewed and discussed from five aspects,i.e.,the analytical framework,the aerodynamic interference,the evaluation criteria,the design loads of long-span bridge and the double-deck railcum-road bridge.The refining process of analysis system is reviewed from the aspects of simulation wind load,vehicle load and bridge structure,and the corresponding coupling relationship.For aerodynamic interference,the development process is summarized from the simulative precision of the elements(wind,vehicle and bridge),the load cases and the object of interference.For evaluation criteria,the corresponding development course is summarized from the certain evaluation method to uncertain one.For long-span bridge design load,the wind and vehicle loads are reviewed and summarized from current multinational codes and theoretical research.For double-deck rail-cum-road bridge,the mechanism of multi-element coupling relationship and corresponding aerodynamic interference are both reviewed.By comprehensive review and summary,the analytical framework is in the process from simplification to refinement.The simulation and consideration of the objects of structural interference gradually become complex.The corresponding simulation theory,wind tunnel scale,test equipment and technology are the key factors to limit its development.For systematic evaluation of vehicle and bridge,the structural and systemic security are the basis of the evaluation,and the auxiliary components and functional evaluation need to be paid more attention.The evaluation criterion will be developed from certain method to reliability assessment.For design load of long-span bridge,the vehicle load is gradually transferred from the simple application of the design load of small-medium span bridge into a complex model considering the load characteristics.For double-deck rail-cum-road bridge,the basic theory and experimental study on coupling mechanism and aerodynamic interference need to be developed.展开更多
基金Project(52025082) supported by the National Natural Science Foundation for Distinguished Young Scholars of ChinaProject(CX20190288) supported by Hunan Provincial Innovation Foundation for Postgraduate,China。
文摘Wind tunnel tests were carried out to investigate the aerodynamic interference between a triple-box girder and trains,involving static aerodynamic forces and vortex-induced vibrations(VIVs).Static and dynamic sectional models of the girder and trains were employed for aerodynamic force measurement and VIV test,respectively.Results indicate that the aerodynamic interference effect on static aerodynamic forces of both the girder and trains is remarkable.When a single train exists,the horizontal position of the train has a small effect on aerodynamic coefficients of the girder.When two trains meet on the girder,the drag coefficient of the girder is significantly reduced compared with that of without train or with a single train;besides,during the whole meeting process,aerodynamic forces of the leeward train first drop and then increase suddenly.The fluctuation of aerodynamic force could cause redundant vibration of the train,which is unfavorable for safety and comfort.A train on the girder could worsen the girder VIV performance:a new vertical VIV appears in the triple-box girder when a train is on the girder,and the torsional VIV amplitude increases significantly when the train is on the windward side.
基金The work was supported by the Ministry of Science and Technology of China through the Fundamental Research Fund for State Key Laboratories(Grant No.SLDRCE08-A-02)the National Nature Science Foundation of China(Grant No.50978204).
文摘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.
基金The work was supported by the National Natural Science Foundation of China(Grant No.50608030).
文摘The aerodynamic interference effects on aero-static 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 com-pared 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.
文摘The correction method uses the static pressures measured near the tunnelwalls during model tests as boundary conditions. It is required that the flow near thewalls is subsonic and the freestream Mach number is less than 1. It is still valid whenthere are shock waves and supersonic pockets near the model as long as shock waves donot extend to walls, and the method is applicable to various ventilated wall or solid walltest sections. Corrections for three models tested abroad are in quite good agreementwith NASA's results, which are obtained by a nonhnear correction method. Thepresnet method has been apphed to B737 inodel tcsted in CARDC 1.2 m wind tunnel.The results show that this method is suitable for transonic wall interference correctionfor high aspect ratio airplane tests.
基金supported by the National Key Research and Development Program of China(2019YFB1600702)General Program of National Natural Science Foundation of China(51878058)+5 种基金National Natural Science Foundation of China(52008027)the General Project Supported by Natural Science Basic Research Plan in Shaanxi Province of China for Young Scientists(2021JQ-269)Fundamental Research Funds for the Central Universities,CHD(300102211304)National Natural Science Foundation of China(51908178)Top Young Talent Program of Higher Learning Institutions of Hebei(BJ2020012)Basic Research Program of Natural Science in Shaanxi Province of China(2019JZ-02)。
文摘To promote and develop the theoretical basis and application of the wind-vehicle-bridge coupling vibration system,the corresponding research status and prospects are reviewed and discussed from five aspects,i.e.,the analytical framework,the aerodynamic interference,the evaluation criteria,the design loads of long-span bridge and the double-deck railcum-road bridge.The refining process of analysis system is reviewed from the aspects of simulation wind load,vehicle load and bridge structure,and the corresponding coupling relationship.For aerodynamic interference,the development process is summarized from the simulative precision of the elements(wind,vehicle and bridge),the load cases and the object of interference.For evaluation criteria,the corresponding development course is summarized from the certain evaluation method to uncertain one.For long-span bridge design load,the wind and vehicle loads are reviewed and summarized from current multinational codes and theoretical research.For double-deck rail-cum-road bridge,the mechanism of multi-element coupling relationship and corresponding aerodynamic interference are both reviewed.By comprehensive review and summary,the analytical framework is in the process from simplification to refinement.The simulation and consideration of the objects of structural interference gradually become complex.The corresponding simulation theory,wind tunnel scale,test equipment and technology are the key factors to limit its development.For systematic evaluation of vehicle and bridge,the structural and systemic security are the basis of the evaluation,and the auxiliary components and functional evaluation need to be paid more attention.The evaluation criterion will be developed from certain method to reliability assessment.For design load of long-span bridge,the vehicle load is gradually transferred from the simple application of the design load of small-medium span bridge into a complex model considering the load characteristics.For double-deck rail-cum-road bridge,the basic theory and experimental study on coupling mechanism and aerodynamic interference need to be developed.
