Study On Numerical Simulation Of Sloshing Forms And Damping Force In Tuned Liquid Damper

Tuned liquid damper (TLD) is an effective vibration control device. The tank is fixed to the structure. When the structure vibrates, the TLD moves with structure and liquid in the tank generates dynamic pressure exerting on the sidewalls. The force is opposite to the moving direction and TLD mitigate the vibration of structure. Meanwhile, the kinetic energy of fluid is dissipated due to the viscosity of the liquid. Comparing to traditional Tuned Mass Damper, TLD’s advantages are low-cost, easy-installed and low maintenance and it could be used temporarily. If there is a liquid storage tank, it could be used as a TLD simultaneously.In this essay, the state of the art and application of TLD and mechanism of TLD vibration control is introduced at first. Researches and methods on sloshing are introduced in next chapter, emphasizing on numerical simulation progress. Based on Constrained Interpolation Profile (CIP) method, computational fluid dynamics numerical model for solving Navier-Stokes equations is proposed. Finite difference method and staggered mesh system are employed. The time integration of the governing equations is based on an Euler method and a fractional step approach in which CIP is used as an interpolation method to solve Navier-Stokes equations. The matrix of Poisson type equation is solved by Bi-Conjugate Gradient Stabilized method. Free surface is captured by Tangent of Hyperbola INterface Capturing (THINC) method, which keeps the moving interface compact and needs no geometry reconstruction. The numerical model could simulate violent free-surface flows. Computation domain is in a tank-fixed coordinate and moving mesh is transformed into body force or acceleration. To validate the model, dam-break problem and sloshing are performed. Two different cases results show that pressure and surface are consistent with experiment data. Sloshing in tank with baffle and without baffle is calculated to ensure that tank-fixed coordinate is reliable and the pressure and surface elevation agrees well with experiment data. The numerical model is efficient and robust.The simulation of TLD including two type of conditions, shallow water TLD and deep water TLD. Two types are simulated under different excitation frequency amplitude and depth to show the response of liquid in TLD. The result reveals that sloshing in shallow water is mainly traveling-wave and wave breaking is violent in cases, which water depth is shallower and nonlinear effect is dominated. The dissipation of energy is effective in shallow water TLD that works in a wide frequency range. Meanwhile, sloshing in deep water TLD is mainly standing wave and wave breaking happens when excitation amplitude is large. The dissipation of energy is low and deep-water TLD works provided the excitation frequency is near to its natural frequency. The damping force increase tends to increase as excitation amplitude increase. Overall, shallow water TLD works better and it is more widely used than deep water TLD.