Research On Flow-induced Vibration Of Airfoil Structure

The airfoil structure is a structure widely used in underwater vehicles,which is prone to flow separation,and then induces strong flow-induced vibration.Based on unidirectional and bidirectional fluid-structure coupling algorithms and statistical energy analysis methods,this paper analyzes the fluid-induced vibration characteristics of fixed-end elastic flat plates,two-dimensional airfoil,three-dimensional straight airfoil,and cone-column combined structures with infinitely large ends.In this paper,firstly,the elastic plate is used as the research object,and the bidirectional fluid-structure interaction algorithm is used to explore the fluid viscosity A numerical simulation of the attenuation and oscillation process of an elastic plate fixedly supported at one end immersed in a stationary fluid is carried out.Comparative analysis with literature values.The calculation results show that the displacement response amplitude and the attenuation oscillation frequency at the assessment point are in good agreement with the literature values,indicating the validity of the two-way fluid-structure coupling algorithm calculation.And the damping oscillation frequency of the elastic plate under different fluid viscosities remains the same.As the fluid viscosity increases,the magnitude of the displacement response at the assessment point also decreases.Based on the experimental data,the validity of the one-way solution method is verified.Secondly,the unidirectional and bidirectional fluid-structure coupling algorithms are applied to the two-dimensional NACA0012 airfoil,and the free flow velocity,wall roughness,angle of attack,and edge form are used to analyze the vortex shedding frequency and wake field vorticity of the airfoil structure Affect the law.Numerical calculation results show that the roughness of large walls will induce low-frequency vortices,and the low-frequency vortex energy decays slowly.Under non-locking conditions,the calculation results of the one-way and two-way coupling algorithms are not much different.The magnitude of the displacement response is mainly concentrated on the trailing edge of the airfoil,which is consistent with the characteristics of the pulsating pressure distribution.Then,the unidirectional fluid-structure interaction method is used to study the three-dimensional equal straight airfoil flow-induced vibration characteristics.The calculation results show that there are multiple vortex emission frequencies along the spanwise direction of the three-dimensional equal straight airfoil,and there are also multiple vortex emission frequencies on the same section.In the calculation frequency band,the three-dimensional airfoil has a large displacement response at the two main vortex shedding frequencies and the second-order bending natural mode of the structure,and the flow-induced vibration response at the vortex frequency is greater than that at the structural vibration mode.Finally,based on the obtained numerical calculation conclusions,the detailed scheme design of the flow-induced vibration verification test of the airfoil structure is carried out.