Numerical Simulations For Soft Hair Anchored Channel Flow With Large Deformation Based On Immersed Boundary Method

Interactions between flexible structures and fluid flow pervasively exist in nature,biological systems,and industrial processes.Studies for these problems are helpful for understanding natural phenomena in a better way and controlling industrial processes properly.In this thesis,we considered the flow in a channel with which the inner surfaces are covered with flexible fibers.The drag character and flow states of the device are investigated by numerical simulations.The 'immersed boundary method' was used here to dealing with the fluid-structure interaction problems with large deformation.Firstly,the influence of the flow and structure parameters on flow state and device's drag property were considered separately.The simulation results indicate that the flow states are affected by both fibre rigidity and Reynolds number.The global tendency is that the flow tends to be steady under small fibre rigidity or low Reynolds number,otherwise,it tends to be unsteady.Also,the drag coefficient of device changes in a different way under different flow state.In steady cases,the drag coefficient spread in a limited zone,while in transient cases,the distribution law is complicated and affected by the fibre rigidity.Besides,the study for the influence of symmetry of structures indicates that no matter the device is symmetric or not,the final state of flow will not be affected.We also discussed the cases with inclining fibers and found that the inclining directions of fibers can obviously affect the device's drag property.After that,we changed the inlet boundary condition to velocity-inlet,and the calculation domain was extended 8 times to the previous.The results show that the distribution law of flow state under this condition has a similar tendency with the results under periodic boundary conditions,although the distribution domain is different.