A series of three-dimensional (3D) transient simulations are carried out to study the onset and features of oscillatory thermocapillary convection in deformed half zone liquid bridges of low Prandtl number fluids (Pr = 0.01) with unit aspect ratio (As). The critical conditions for different volume ratios on ground and under microgravity are determined. It turns out that the threshold of the second bifurcation is more sensitive to volume ratio than the first bifurcation. The thresholds in deformed liquid bridges are usually higher than those in cylindrical liquid bridges. The critical azimuthal wavenumber increases from 2 to 3 with volume ratio. Gravity affects the flow through three factors. Compared with the hydrostatic deformation and heating orientation, buoyancy is marginal to the flow transition. It only affects the threshold and the deviation caused by buoyancy is within 2%. The effects of gravity on the critical conditions are dependent on volume ratio. Except for the threshold, gravity may also affect the critical azimuthal wavenumber and the critical oscillation mode. 3D oscillatory flow regimes with two different oscillation modes are present. A new type of “Rocking” mode is discovered in the present study.

一系列三维（3D）瞬态仿真的被执行来研究发生和设有振荡热毛细对流在变形低普朗特数的流体（半区的液体桥镨 = 0.01）与单元的纵横比（如）。确定了地面和微重力下不同体积比的临界条件。结果表明，第二个分叉的阈值比第一个分叉对体积比更敏感。变形液桥的阈值通常高于圆柱形液桥的阈值。临界方位波数随体积比从 2 增加到 3。重力通过三个因素影响流量。与流体静力变形和加热取向相比，浮力对于流动过渡是边缘的。只影响阈值，浮力引起的偏差在2%以内。重力对临界条件的影响取决于体积比。除阈值外，重力还可能影响临界方位波数和临界振荡模式。存在具有两种不同振荡模式的 3D 振荡流态。本研究发现了一种新型的“摇摆”模式。