Numerical Investigation Of Fluid-Structure Interaction Of Circular Cylinder-Splitter Plate System

Flow over the circular cylinder-splitter plate system is one of the problems of fluid-structure interaction.The related investigation under low Reynolds number is significant to practical engineering.Dynamic characteristics of the circular cylinder-splitter plate system in rotary oscillation,in rotary oscillation and transverse vibration and two circular cylinder-splitter plate systems in tandem arrangement are investigated.The simulation is conducted by a two-dimensional numerical model to study the basic aspects of fluid-structure interaction.In the frame of Arbitrary Lagrangian-Eulerian?ALE?,a model of fluid-structure interaction is developed.The Navier-Stokes equations of incompressible viscous fluid are solved by the Finite Element Method,which is a high order Taylor-Galerkin upwind scheme.The motion equations of structures are solved by Newmark-?method.And the mesh is updated through a suitable strategy.Validated carefully against typical problems,the model is employed to invstegate the fluid-structure interactions.Firstly,numerical simulations are conducted to investigate the rotary oscillation of circular cylinder-splitter plate system.The influence of mass ratio and rotary reduced velocity on the characteristics of oscillation are exmained,especially the effect of mass ratio on bifurcation.From the numerical results,bifurcation occurs after the rotary reduced velocity is bigger than the critical value Urr₁,which increases linearly with mass ratio.And even-times frequencies of predominant frequency and asymmetrical characteristics of flow filed are discovered after bifurcation.The characteristics of field flow shows that the appearance of bifurcation is attributed to the symmetry breaking.The rotary amplitude and predominant frequency jump at a particular reduced velocity Urr₂,which increases with mass ratio.Secondly,the fluid-structure interaction of circular cylinder-splitter plate system in rotary oscillation and transverse vibration are studied.The influences of rotary and transverse reduced velocity on the dynamic responses of the system are investigated.The results show that bifurcation will not occur even at higher rotary reduced velocities under specific transverse reduced velocities.In the rest of transverse reduced velocities,rotary and transverse bifurcation will occur at same time on the same side after rotary reduced velocity is bigger than the critical value.Both rotary and transverse reduced velocity have effects on the amplitude,and the increase of amplitude is related to the change of wake vortex pattern after bifurcation.Finally,the flow interference between the two circular cylinder-splitter plate systems in tandem arrangement are investigated,with same structural dynamic parameters in rotation and transverse vibration.The influences of reduced velocity and spacing ratio on characteristics of vibration and flow field are mainly studied.The results show that the maximum amplitude,equilibrium position and the frequency of rotation and transverse vibration are not affected by spacing ratio in the range of 8.0,10.0 and 12.0.And the corresponding characteristics of upstream system are close to the single system.In the wake of upstream system,the characteristics of downstream system change more complexly with reduced velocities.Both space ratio and reduced velocity influence the wake vortex pattern.