A three-dimensional mathematical hydrodynamic model associated with surface wave radiation by a floating rectangular box-type structure due to heave,sway,and roll motions in finite water depth is investigated based on...A three-dimensional mathematical hydrodynamic model associated with surface wave radiation by a floating rectangular box-type structure due to heave,sway,and roll motions in finite water depth is investigated based on small amplitude water wave theory and linear structural response.The analytical expressions for the radiation potentials,wave forces,and hydrodynamic coefficients are presented based on matched eigenfunction expansion method(MEFEM).The correctness of the analytical results of wave forces is compared with the construction of a numerical model using the open-source boundary element method code NEMOH.In addition,the present result is compared with the existing published experimental results available in the literature.The effects of the different design parameters on the floating box-type rectangular structure are studied by analyzing the vertical wave force,horizontal wave force,torque,added mass,and damping coefficients due to the heave,sway,and roll motions,and the comparison analysis between the forces is also analyzed in detail.Further,the effect of reflection and transmission coefficients by varying the structural width and drafts are analyzed.展开更多
The temperature distributions of a prestressed concrete box girder bridge under the effect of cold wave processes were analyzed. The distributions were found different from those under the effect of solar radiation or...The temperature distributions of a prestressed concrete box girder bridge under the effect of cold wave processes were analyzed. The distributions were found different from those under the effect of solar radiation or nighttime radiation cooling and should not be simplified as one dimensional. A temperature predicting model that can accurately predict temperatures over the cross section of the concrete box girder was developed. On the basis of the analytical model, a two-dimensional temperature gradient model was proposed and a parametric study that considered meteorological factors was performed. The results of sensitivity analysis show that the cold wave with shorter duration and more severe temperature drop may cause more unfavorable influences on the concrete box girder bridge. Finally, the unrestrained linear curvatures, self-equilibrating stresses and bending stresses when considering the frame action of the cross section, were derived from the proposed temperature gradient model and current code provisions, respectively. Then, a comparison was made between the value calculated against proposed model and several current specifications. The results show that the cold wave may cause more unfavorable effect on the concrete box girder bridge, especially on the large concrete box girder bridge. Therefore, it is necessary to consider the thermal effect caused by cold wave during the design stage.展开更多
An experiment that investigates the interactions between dam-break flow and a floating box is reported in this paper.The interaction processes are described in detail,and the effects of reservoir depth,clearance betwe...An experiment that investigates the interactions between dam-break flow and a floating box is reported in this paper.The interaction processes are described in detail,and the effects of reservoir depth,clearance between the structure and vertical wall,and structure motion on the observed interactions are discussed.Results indicate that interactions are mild if the reservoir depth is relatively small and most of the water flows through under the structure.However,as the reservoir depth increases,the interactions intensify,and overtopping and wave splashing occur.The incident wave is divided into two parts by the structure:1)a jet generated by wave impact and 2)the water flowing through under the structure.The water flowing through under the structure is the main factor influencing the motion of the structure.The phenomenon of secondary slamming is observed in all of the test cases,and the relative motion of the structure and free surface explains the occurrence of secondary slamming.展开更多
基金the project Hydroelastic behaviour of horizontal flexible floating structures for applications to Floating Breakwaters and Wave Energy Converters(HYDROELASTWEB),which is co-funded by the European Regional Development Fund(Fundo Europeu de Desenvolvimento Regional-FEDER)by the Portuguese Foundation for Science and Technology(Funda??o para a Ciência e a Tecnologia-FCT)under contract 031488_770(PTDC/ECI-EGC/31488/2017)+1 种基金a Researcher by FCT,through Scientific Employment Stimulus,Individual support under Contract No.CEECIND/04879/2017the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering(CENTEC),which is financed by the Portuguese Foundation for Science and Technology(Funda??o para a Ciência e Tecnologia-FCT)under contract UIDB/UIDP/00134/2020。
文摘A three-dimensional mathematical hydrodynamic model associated with surface wave radiation by a floating rectangular box-type structure due to heave,sway,and roll motions in finite water depth is investigated based on small amplitude water wave theory and linear structural response.The analytical expressions for the radiation potentials,wave forces,and hydrodynamic coefficients are presented based on matched eigenfunction expansion method(MEFEM).The correctness of the analytical results of wave forces is compared with the construction of a numerical model using the open-source boundary element method code NEMOH.In addition,the present result is compared with the existing published experimental results available in the literature.The effects of the different design parameters on the floating box-type rectangular structure are studied by analyzing the vertical wave force,horizontal wave force,torque,added mass,and damping coefficients due to the heave,sway,and roll motions,and the comparison analysis between the forces is also analyzed in detail.Further,the effect of reflection and transmission coefficients by varying the structural width and drafts are analyzed.
基金Project(08Y60) supported by the Traffic Science’s Research Planning of Jiangsu Province,China
文摘The temperature distributions of a prestressed concrete box girder bridge under the effect of cold wave processes were analyzed. The distributions were found different from those under the effect of solar radiation or nighttime radiation cooling and should not be simplified as one dimensional. A temperature predicting model that can accurately predict temperatures over the cross section of the concrete box girder was developed. On the basis of the analytical model, a two-dimensional temperature gradient model was proposed and a parametric study that considered meteorological factors was performed. The results of sensitivity analysis show that the cold wave with shorter duration and more severe temperature drop may cause more unfavorable influences on the concrete box girder bridge. Finally, the unrestrained linear curvatures, self-equilibrating stresses and bending stresses when considering the frame action of the cross section, were derived from the proposed temperature gradient model and current code provisions, respectively. Then, a comparison was made between the value calculated against proposed model and several current specifications. The results show that the cold wave may cause more unfavorable effect on the concrete box girder bridge, especially on the large concrete box girder bridge. Therefore, it is necessary to consider the thermal effect caused by cold wave during the design stage.
基金the National Key Research and Development Program of China(No.2016YFC0303401)the National Natural Science Foundation of China(No.51779236)the National Natural Science Foundation of China-Shandong Joint Fund(No.U1706226)。
文摘An experiment that investigates the interactions between dam-break flow and a floating box is reported in this paper.The interaction processes are described in detail,and the effects of reservoir depth,clearance between the structure and vertical wall,and structure motion on the observed interactions are discussed.Results indicate that interactions are mild if the reservoir depth is relatively small and most of the water flows through under the structure.However,as the reservoir depth increases,the interactions intensify,and overtopping and wave splashing occur.The incident wave is divided into two parts by the structure:1)a jet generated by wave impact and 2)the water flowing through under the structure.The water flowing through under the structure is the main factor influencing the motion of the structure.The phenomenon of secondary slamming is observed in all of the test cases,and the relative motion of the structure and free surface explains the occurrence of secondary slamming.
