Numerical Research Of Vortex-Induced Vibration Suppression Of 3D Circular Cylinder Using A Splitter Plate

Cylinder structure widely exists in nature and ocean engineering fields,including columns of offshore platforms,columns of floating wind turbines,marine risers are all cylindrical structures.When the fluid flows through the cylinder structure,there may be periodic alternating vortices behind the cylinder in a certain flow state,and the periodic vortex shedding induces the periodic fluid force acting on the cylinder.When the vortex shedding frequency is close to the natural frequency of the structure,on the one hand,the periodic fluid force makes the cylinder resonate;on the other hand,the periodic vibration of the cylinder may lock the vortex shedding frequency and cause severe lateral vibration of the structure.The coupling phenomenon between the fluid and the structure caused by vortex shedding is called vortex-induced vibration(VIV),which can cause damage to structures and cause huge loss of personnel and property.Therefore,researchers pay more and more attention to the suppression of VIV.In this paper,the VIV suppression problem of a cylinder was studied by designing a rigid attached splitter plate in the back pressure region of the cylinder wake.The Detached-Eddy Simulation turbulence model was used to carry out the numerical prediction of the vortex-induced vibration suppression of the cylinder,and different types of DES turbulence models were discussed and analyzed in detail.Based on the two-way fluid structure interaction,the full coupling algorithm of FSI was explored,and the numerical realization method of two-way fluid structure coupling and the numerical prediction technology of vortex-induced vibration of cylinder with two-way fluid structure interaction were studied.Based on the wake oscillator model and structural dynamics principle,the two-way coupled numerical model of vortex-induced vibration of a single cylinder was established in ANSYS Workbench by using computational fluid dynamics software ANSYS CFX.In this paper,the effect of splitter plate on vortex-induced vibration of a cylinder in subcritical Reynolds number region was numerically simulated by using DES turbulence model.Firstly,three amplitude response branches of single cylinder vibration with low mass damping ratio and corresponding different wake shedding modes were successfully simulated.On this basis,the vibration of cylinder with rigid splitter plate at different reduced speeds were further studied dynamic response,it have been found that the vibration response of the cylinder was divided into "vortex-induced vibration suppression region" and "galloping region".The influence of the splitter plate on the amplitude,fluid force,vortex shedding frequency and wake shedding modes of the vibrating cylinder under different reduced speeds have been explored.The suppression mechanism of the splitter plate on the vortex-induced vibration of the cylinder and the main factor causing galloping have been revealed.