Study On The Dynamic Characteristics Of Fluid In The Fluid Storage Tank With Two Layers Of Different Rigid Baffles

The fluid sloshing is widely existed in various fields of engineering,and it will cause great damage to the engineering structure once the fluid storage tank is externally stimulated by the complex flow-solid coupling.Therefore,it is necessary to analyze the dynamic response mechanism of the fluid inside the tank.In this paper,based on the fluid sub-domain method and the finite element analysis software ADINA,the dynamic characteristics of fluid in the fluid storage tank with two layers of different rigid baffles is investigated as follows:(1)For cylindrical fluid storage tank with two different baffles,the complex fluid domain was divided into eight simple sub-domains according to the principle of fluid sub-domain method division.The trial function of the velocity potential of each sub-domain was solved using the superposition principle and the separation of variables method,in which the coefficients to be determined from the continuity conditions between the sub-domains and the kinetic boundary conditions of the free fluid surface.The eigenequations on frequency and mode were obtained through converting the series equations into a linear system of equations by generalized Fourier expansion.The method of solving the generalized eigenvalues was used to determine the coefficients to be determined.Convergence and comparison studies verify the high accuracy and correctness of the fluid sub-domain method,and the effect of the baffle parameters on the fluid sloshing characteristics was discussed in detail.(2)On this basis,the fluid sloshing response in a cylindrical storage tank with two layers of different baffles under horizontal excitation was investigated.The absolute velocity potential of the fluid was superimposed by the rigid body velocity potential and the perturbation velocity potential.Generalized coordinates were introduced in the perturbation velocity potential,and the dynamic response equations of the fluid storage system were established by the kinematic and kinetic equations of the free fluid surface.The problem was solved using the Duhamel integral to give the analytical solution in the dynamic response equation.The solution of this work was compared with the ADINA solution to verify the correctness of the fluid sub-domain method,and the influences of the baffle parameters on the liquid surface wave height,the resultant hydrodynamic force and the resultant hydrodynamic moment was discussed in detail.(3)In this paper,the fluid sub-domain method was further applied to study the dynamic response of a cylindrical fluid storage system with different baffles under pitching excitation.The fluid velocity potential contains two components: the fluid sloshing velocity potential and the Stokes-Joukowski potential.Generalized coordinates were introduced in the free fluid surface wave height function and fluid velocity potential,respectively.Using the idea of solving the fluid sloshing velocity potential,the analytical solution of the Stokes-Joukowski potential was obtained according to the boundary conditions.The free fluid surface equation was used to establish the dynamic response equation about the generalized coordinates.The solution of this work was compared with the ADINA solution to verify the correctness of the fluid sub-domain method,and the influences of the baffle parameters on the liquid surface wave height,the resultant hydrodynamic force and the resultant hydrodynamic moment was discussed in detail.(4)Finally,the dynamic response of a two-dimensional fluid storage system with two different baffles under horizontal excitation was investigated using the finite element analysis software ADINA.The wave height response was calculated for a single baffle and a double layer with different baffles.The wave height responses in both cases were compared to verify the effectiveness of the double-layer baffle.The effect of doublelayer baffle parameters on the fluid sloshing response was investigated,and the mechanism of vortex evolution was discussed.