Analysis Of Flow-induced Vibration Of Cylinder With Splitter Plate Based On Overset Grid Method

Flow-induced vibration is a common phenomenon in nature,which will reduce the stability of the structure and may even cause the fatigue damage of the structure.However,as long as the vibration energy is collected efficiently,a large amount of clean energy can be obtained.Therefore,the research on vibration control has attracted widespread attention,and the partition plate installed behind the bluff body has always been an effective passive control technology.Overset grids is a unique way of processing dynamic grids.Its basic idea divides the grid into two parts: a background grid and a body-fitted grid.The two sets of grids do not need to be in common or coplanar.The calculation of the flow field is completed by the mutual interpolation of the overlapping areas between the grids,which can effectively solve the problem of moving grids in unsteady flow.In this paper,a numerical analysis method is used to simulate a cylinder-divider system with two degrees of freedom elastically supported under high Reynolds number.Based on the way of overlapping grids,it can simulate the movement with large grid deformation.In this paper,the vortex-induced vibration response,motion trajectory and flow field characteristics of the vibrating system are obtained through research and analysis,and the influence of the partition plate on the vibration control of the system under different parameters is considered.The work completed in the paper is as follows:1 The hydrodynamic coefficients of the fixed cylinder and the vibration characteristics of the elastically supported single cylinder system are calculated by fluidsolid coupling.Numerical simulations show the existence of the locked vibration zone.The cylindrical vibration system in the locked vibration zone will have a larger amplitude and the frequency is The natural frequency is close,which is easy to cause damage;the transition process of the vortex detachment mode of the cylindrical wake from 2S to 2P and then to 2S with the change of the reduced speed is obtained.The comparison and analysis with the existing experiments and research results show that the calculation method used in this paper is reasonable.2 The effect and influence of the partition plate on the cylindrical vibration system under different reduced speeds are analyzed.The amplitude of the cylinder-divider system is approximately linear with the reduction speed.As the reduction speed increases,the amplitude of the cylinder-separator system will continue to increase.The reduction speed in the calculation area does not show a tendency to decrease the amplitude.The calculation results show that the cylinder-divider system has the characteristics of higher amplitude and lower frequency at high reduced speed,which can prevent the system from resonant damage and be used as a vibration energy harvesting device.3 The effect and influence of the partition plate under different plate lengths on the cylindrical vibration system are analyzed,and the vibration response and wake characteristics of the plate length L/D of the partition plate from 0 to 1.3 are obtained.The calculation results show that under high Reynolds number,the lower plate length can also affect the drag coefficient of the system,which reaches the lowest value when the L/D is 0.8;the vortex frequency also gradually decreases with the increase of the plate length Afterwards,it tends to be stable;when the board length is low,it does not have a significant impact on the movement trajectory and presents a figure of eight.As the length of the board increases,the movement trajectory presents an irregular figure of eight.4 The effect and influence of the partition plate on the cylindrical vibration system under different deflection angles are analyzed.The research results show that when the declination angle is low,the partition plate has limited influence on the system;when the deflection angle is about 10 degrees,the vibration characteristics of the system will have a sudden change,the amplitude will decrease,and the vortex frequency will increase;at the deflection angle of 10 degrees to 45 degrees As the declination angle increases,the amplitude increases,and the vortex frequency decreases;it can be seen from the motion trajectory that the declination angle changes suddenly after 10 degrees,and the system has a small amplitude between 10 degrees and 25 degrees.,That is,in this declination interval,the partition plate has a better control effect on the vibration of the cylindrical system.