@techreport{oai:jaxa.repo.nii.ac.jp:00042953, author = {Liang, R. Q. and N.Esfahany, M. and 川路, 正裕 and Liang, R. Q. and N.Esfahany, M. and Kawaji, Masahiro}, month = {Aug}, note = {The effects of small vibrations on Marangoni convection were investigated using a liquid bridge of 5cSt silicone oil with a disk diameter of 7.0 mm, and an aspect ratio close to 0.5. Experiments were performed to determine the critical temperature difference data for no vibration case and with small vibrations applied. The surface oscillation amplitude was also determined experimentally, and a 3-D numerical simulation model was developed using a level set algorithm to predict the surface oscillations of an isothermal liquid bridge. The experimental results have shown that the effect of small vibrations on the onset of oscillatory flow is small since the critical temperature difference data for different aspect ratios were not affected by the vibrations. This is consistent with the results obtained for acetone bridges reported in the previous year. The peak amplitudes of surface oscillations decreased as the disk temperature difference was increased and the average liquid temperature decreased. This can be attributed to an increase in surface tension which stabilizes the liquid bridge surface. The surface oscillation amplitude, however, showed an abrupt increase at the onset of oscillatory Marangoni convection, and then a decrease as the temperature difference was further increased above the critical value. The reason for this variation in the surface oscillation amplitude with the temperature difference is unclear and needs to be investigated further. To clarify the surface oscillation phenomena induced by external vibrations, experiments and numerical simulations were conducted for an isothermal silicone oil bridge of 7.0 mm diameter. By subjecting the liquid bridge to small random vibrations, the surface oscillation frequency could be clearly determined. The computational results have also shown a similar surface oscillation frequency., 資料番号: AA0046980004, レポート番号: NASDA-TMR-030004E}, title = {Effects of small vibrations on Marangoni convection in a liquid bridge and numerical simulation of surface oscillation}, year = {2003} }