矩形液池热毛细对流转捩途径研究

主要研究矩形液池热毛细对流的分岔转捩. 通过测量流体内部温度振荡情况, 详细研究了热毛细对流的转捩过程和转捩途径. 实验发现, 矩形液池热毛细对流的转捩过程依次经历了定常、规则振荡、不规则振荡的阶段. 对于不同普朗特数的硅油在不同长高比情况下, 通向混沌的途径不同. 在转捩过程中, 随着温差的增加, 普朗特数在16 (1cSt) 以下和普朗特数为25 (1.5cSt)、长高比为26 的硅油热毛细对流主要以准周期分岔的转捩方式为主;而普朗特数为25 以上的则以倍周期分岔的转捩方式为主;两种分岔有时还会伴随有切分岔形式的出现.实验中还观察到了表面波动和对流涡胞振荡等现象.

STUDY ON TRANSITION TO CHAOS OF THERMOCAPILLARY CONVECTION IN A RECTANGULAR LIQUID POOL

This paper mainly does the experimental research about transition to chaos of thermocapillary convection in the rectangular pool. In the experiment, we observed that the transition process of thermocapillary convection in the rectangular pool has different phases of steady, regular oscillation and irregular oscillation. For different Prandtl numbers of silicone oil in different aspect ratios, there are different transition routes to chaos. When Prandtl number of silicone oil is less than or equal to 16 (1cSt) or Prandtl number equal to 25 (1.5cSt) with aspect ratios of 26, thermocapillary convection transition follows quasi-periodic bifurcation routes to chaos as the temperature increases. But when silicone oil of Prandtl number is greater than or equal to 25, it mainly follows period-doubling bifurcation routes to chaos. Sometimes two types of bifurcation would be accompanied by emergence of tangent bifurcation. In the experiment, we observed the distribution of the temperature field of liquid surface by using thermal imaging cameras, and found some phenomena of the surface fluctuation and convective cell oscillation.