A numerical and experimental study on the sloshing behaviours of cylindrical and rectangular liquid tanks is addressed. A three-dimensional boundary element method for space with the second-order Taylor series expansion in time is established to simulate the sloshing phenomenon and its related physical quantities inside a liquid tank subjected to horizontal harmonic oscillations or recorded earthquake excitations. The small-scale model experiments are carried out to verify some results of numerical methods in this study. The comparisons between numerical and experimental results show that the numerical method is reliable for both kinds of ground excitations. Finally, the water wave and the base shear force of a rectangular tank due to harmonic excitation are also presented at different frequencies. A huge cylindrical water tank subjected to a recorded earthquake excitation is used for application and discussion.

SUMMARYIn this article, a non-singular formulation of the boundary integral equation is developed to solve smooth and non-smooth interior potential problems in two dimensions. The subtracting and adding-back technique is used to regularize the singularity of Green's function and to simplify the calculation of the normal derivative of Green's function. After that, a global numerical integration is directly applied at the boundary, and those integration points are also taken as collocation points to simplify the algorithm of computation. The result indicates that this simple method gives the convergence speed of order N −3 in the smooth boundary cases for both Dirichlet and mix-type problems. For the non-smooth cases, the convergence speed drops at O(N −1=2 ) for the Dirichlet problems.

This study presents a numerical method to describe and predict the phenomena of three-dimensional nonlinear liquid sloshing problem of a tuned liquid damper (or TLD) to any kind of forced motion. The three-dimensional boundary element method with the second-order Taylor series expansion and Lagrangian description is established and used to compute the position and other quantities of the liquid particles in the liquid domain and on the free surface. The calculations of transient solution (or the time history) of the free surface movement and the base shear force from hydrodynamic pressures of a three-dimensional rectangular or cylindrical TLD tank subjected to horizontal harmonic forced oscillation, as two examples, are included in this paper for demonstration and discussion.

SUMMARYThe active control of a Tuned Liquid Column Damper (TLCD) with two propellers is presented. A single-degree-of-freedom system with a passive or active TLCD is used as an example to set up the basic equation of motion. The Optimal Control Theory is applied to establish the control law and to calculate the control force generated by these two propellers installed inside the TLCD. A simple pendulum-like model test is carried out to study the dynamic characteristics of the passive and active TLCDs and the e ectiveness of the vibrational control. Comparison of the experimental result with the analytical one shows a good agreement. Finally, the analytical results of the seismic response are also included as an example for demonstration and application.

A proposed mass-coupling structural mechanism is presented in this paper to represent a TLCD attached to a main structural system. It is a simple structural model and can be applied to the structural analysis of any complicate structure by use of the finite element method. The effectiveness of a passive or active TLCD in vibrational reduction of a five-story shear building subjected to earthquake is included as an example for demonstration and discussion.