Analytical model of liquid sloshing for tuned liquid damper application | |
| Author | Tospol Pinkaew |
| Call Number | AIT Thesis no. ST-93-15 |
| Subject(s) | Vibration--Mathematical models Dampness in buildings |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | An analytical model of liquid sloshing is developed for the design of tuned liquid damper (1LD). Unlike the previous studies, an attempt is made to propose a simpler model which can accurately predict the basic important characteristics of liquid sloshing. This model is formulated by using a new approach combining the potential flow theory with the Lagrange equation. The obtained model is expressed in the form of generalized coordinates which can be physically related to the free surface amplitude of sloshing. Since the damping of pure water is insufficient for damper application, the flow obstruction devices are introduced so as to achieve the adequate damping. Based on Quasi-steady assumption, the induced damping is derived analytically and included in the obtained model. The damping produced by the obstructions is found to be nonlinear, so the perturbation technique is adopted to estimate the sloshing responses due to the harmonic tank motion. Experiments of the scaled 1LD-tank: model are performed on shaking table to confirm the validity of the proposed analytical model. The natural frequency and damping ratio are obtained from free oscillation test. On the other hand, the frequency responses of the sloshing force, free surf ace elevation, and phase difference between liquid responses and excitation are measured from forced oscillation test. These experimental results are in good agreement with the model predictions. In addition, to predict the induced damping due to the obstruction screen, the simple flow resistance test is separately conducted to obtain the screen drag coefficient, which is found to be a nonlinear function of Reynolds number. Based on this drag function, the sloshing modal damping is predicted and compared with the damping obtained from free vibration test. Fairly good agreement between both is found. This study is believed to provide the essential elements for the practical design of TLD in which the proposed analytical model is used to describe the liquid motion while the data flow resistance test is used for prediction of the sloshing modal damping. |
| Year | 1993 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pennung Warnitchai ; |
| Examination Committee(s) | Worsak Kanok-Nukulchai ;Karasudhi, Pisidhi ; Sugiyama, Toshiyuki |
| Scholarship Donor(s) | King's scholarship ; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1993 |