Study On Parameters Of Aerodynamic Force Of Helically Wired Stay Cable

In recent years, many countermeasures have been taken in projects to solve theproblem of Rain-Wind-Induced Vibration of cables and good effect is achievedafterwards. Wrapping helical wires on the surface of stay cables is an effectivemethod. Although the effectiveness of this method is testified by a great number ofstudies and practice, there are still some questions that need to be further studied,such as whether or not the drag force of cables with spiral wires gets larger than thatof smooth ones, how is the vortex shedding and how is the axial correlations of wakevelocity and aerodynamic force of that kind of cables.This paper attends to study various aerodynamic parameters including thecoefficients of aerodynamic force, the frequency of vortex shedding, the axialcorrelations of wake velocity and aerodynamic force etc, by joint use of wind tunneltest and CFD numerical simulation. In this paper,10kinds of cable models are firstlydesigned and made, and then tested under5different speeds of velocity, Reynoldsnumber ranges from4×10~4to1.6×10~5. Based on the results of experiments, theaxial distribution of mean pressure on cable surface, the magnitude of aerodynamicforce coefficient, the frequency of vortex shedding, and the axial correlation ofpressure on smooth cables and wired cables are studied under5different Reynoldsnumbers. The code of Fluent in Ansys13.0is finally used for calculation for everykind of cables, which provides a good complement to the experiment, and someresults or conclusions of CFD calculation are compared with that of experiment andarticles, thus the mechanism and effectiveness of spiral wires to cables are discussedand studied. The results of experiment and CFD show that: The average dragcoefficient of smooth cables is larger than that of wired cables; the axial correlationsof wake velocity, surface pressure and aerodynamic force of smo oth cables are betterthan that of wired cables when Reynolds number ranges from4×10~4to1.6×10~5;Spiral wires have a good effect on suppressing the vortex shedding and the oscillationof stay cables. Through combination use of experiment and numerical simulation, thecharacteristic and discrepancy between smooth cable and wired cable are betterrecognized, the mechanism and effectiveness of vibration mitigation of helical wiresare clearly recognized, and the effectiveness of vibration mitigation under d ifferentparameters of helical wires is better evaluated. Finally, this paper is summarized, and advices on the study of countermeasuresto mitigate vibration of cables in future are posed.