Sim Bok-Cheol, Kim Woo-Seung, Zebib Abdelfattah
Department of Mechanical Engineering, Hanyang University, Seoul, Korea.
Adv Space Res. 2004;34(7):1627-34. doi: 10.1016/j.asr.2004.09.003.
Thermocapillary convection in a differentially heated liquid bridge is investigated in a two-dimensional numerical study. The deformable free surface is obtained as a solution of the coupled transport equations at fixed unit Prandtl number and aspect ratio. Only steady convection can be realized in this axisymmetric computation with either non-deformable or deformable surfaces. Dynamic free-surface deformations do not induce transitions to oscillatory convection even at large Reynolds numbers. Free surfaces are convex near the cold wall due to large surface pressures at the stagnation-point. Near the hot wall they change from concave to convex with increasing Re due to large normal viscous stresses. Large Capillary numbers cause additional surface ripples there while having little effect on the interior. Heat loss from the free surface has dramatic influence on the dynamics and must be included in theoretical models of thermocapillary instabilities.
在一项二维数值研究中，对差动加热液桥中的热毛细对流进行了研究。可变形自由表面是在固定的普朗特数和纵横比下，作为耦合输运方程的解而得到的。在这种具有不可变形或可变形表面的轴对称计算中，只能实现稳态对流。即使在大雷诺数下，动态自由表面变形也不会导致向振荡对流的转变。由于驻点处的大表面压力，自由表面在冷壁附近是凸的。在热壁附近，由于大的法向粘性应力，它们随着雷诺数的增加从凹形变为凸形。大毛细管数在那里会引起额外的表面波纹，而对内部影响很小。自由表面的热损失对动力学有显著影响，必须纳入热毛细不稳定性的理论模型中。
