Wind Tunnel Test On The Aerodynamic Characteristics Of Noncircular Cables

The dry cables of galloping and rain excitations will cause serious damage to cable-stayed bridges.Cable’s aerodynamic performance is also a hot topic in wind engineering Researchers in the study of stay cables generally diagonal cable cross-section default is the standard circular,but with the service life of the cable stayed on the surface of the polyethylene jacket will be due to wind and sun will produce irregular deformation Resulting in deformation of the stay cable section,while the production error of the stay cable,transport bump,winter surface icing and other phenomena will make the deformation of the stay cable section,In addition,only the drag coefficient of the cable with standard circular section is used in the specification.The actual cable stays in and out.Therefore,it is necessary to study the aerodynamic forces of cable-stayed cable.In view of the above problems,the wind tunnel test method is used to systematically study the aerodynamic performances of three types of elliptical cross-section cables and standard circular cross stay cables.The main contents of the study are as follows:(1)In this article,the aerodynamic forces of three different sized diagonal cable stays are studied.By changing the wind direction angle,the three-component coefficients of the model in the subcritical region,critical region,and supercritical region are obtained.The experimental results show that in any model,the drag coefficient increases with the increase of the wind direction angle;when the wind direction angle is between 0° and 50°,the critical area of Reynolds number appears obviously in the non-circular cross-section model relative to the circular cross-section model.The phenomenon is advanced,and the advancement of Reynolds number is sharp with the increase of wind direction angle;when the wind direction angle is between 60° and 90°,the Reynolds number critical area of the non-circular section model must be placed behind the critical section of the Reynolds number of the circular section model.(2)The Reynolds number was divided according to the subcritical region,critical region,and supercritical region of the test data.The drag coefficients of various cross-section models were fitted by the optimal fitting formula,and the resistances of different cross-section inclined cable models were obtained.The range of the coefficient.This provides a relatively complete reference for the study of the non-circular cross-section cable tension coefficient.(3)By analyzing the lift time history of the standard circular cable stayed cable model and the three non-circular cable stayed cable models,the flow field around each model was obtained,and the Reynolds number of the three boundaries of the model boundary layer was specifically divided.range.(4)According to Den Hartog’s determination criteria,three types of non-circular cross-section models can be obtained.