Numerical Investigation Of Flexible Plate In Shear Flow

Fluid-structure interaction problems have always been a hot topic in engineering applications.Due to its multidisciplinary nature,the current research on fluid-structure interaction is still challenging.In this paper,the finite element-immersed boundary-lattice Boltzmann method is used to study two fluid-structure interaction problems:1)The deformation of the plate in the shear flow is studied.It is found that the deformation of the plate in the shear flow is most affected by the bending stiffness.The plate with small bending stiffness has large deformation. is used to define the velocity gradient,The smaller is,the larger the plate deformation is.The effects of shear flow velocity gradient and plate bending stiffness on plate resistance coefficient and pressure distribution around the plate are discussed.The plate with larger mass ratio has larger amplitude of flapping in the process of plate deformation,but does not affect the final deformation.The plate with larger aspect ratio will increase the flapping amplitude and final deformation of the plate,but the increase is small.2)The dynamics of the inverted flexible plate in the shear flow is studied.Three typical deformation modes are found,which are the deflected mode,the flapping mode and the straight mode,respectively.The most affected deformation mode is the bending stiffness and the aspect ratio of the plate.The flapping mode of the plate is asymmetric,when the bending stiffness is small,the flapping amplitude on the high-speed side of the shear flow is large,and the bending stiffness coefficient is large.The flapping amplitude is large on the low-speed side,and the flexible plate with large aspect ratio not only has a large maximum bending potential energy in the flapping mode and the deflected mode,but also has a greater conversion efficiency to fluid kinetic energy,and in shear flow,The conversion efficiency on the low speed side is greater than the on the high speed side.In addition,the influence of the angle of attack of the shear flow on the deformation is also studied.It is found that the flapping mode appears when the angle is 10°,and the maximum value of the bending potential energy is large,but both the mean value and the conversion efficiency are small,and the vortical structures and pressure distribution around the plate are given to discuss the connection of the evolution of vortices with the plate deformation.