In order to obtain the fundamental knowledge of free-surface flows under low-gravity conditions, the unsteady deformations of liquid surface in cylindrical vessels were experimentally observed with a drop tower. Main concern was focused on the dynamic behavior of the liquid driven by surface force and wetting, and the flow fields were found to be governed by the similarity rule described by Weber number. In addition, the algorithm of CIP-LSM, a numerical method for three-dimensional free-surface flows, was restructured on the basis of TCUP scheme, Level Set Method and MARS. The observed flow fields were also simulated by the developed code and the numerical results showed a good agreement with the corresponding experimental data.