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在流体力学领域,流体自由面变化是非常重要的物理现象.研究了矩形池内由液池两端温度差引起的热毛细对流的流体表面变形和表面波问题.该液池的水平横截面尺寸为52mm×42mm,液池内盛有液层厚度为3.5mm的1000号硅油.实验过程中液池两端温度差逐渐增加,液层内流体的流动从稳定的对流逐渐转变为不稳定状态.实验中将Michelson光学干涉测量技术与图像处理技术相结合,发展形成一种实时诊断流体表面形貌的实验测量系统.应用Fourier变换方法对激光干涉条纹图像进行了计算和分析,得到了流体表面变形和表面波的定量的实验结果.实验结果表明在热毛细对流的发展过程中,首先出现流体的表面变形,液池两端温度差达到一定值之后,在该变形的基础上,会有表面波的信息叠加在其中,该表面变形和表面波与流体的温度梯度、表面张力等有直接的关系;表面波隐藏在表面变形内.
In the field of fluid mechanics, the change of fluid free surface is a very important physical phenomenon.The fluid surface deformation and surface wave problem of hot capillary convection caused by the temperature difference between both ends of the liquid pool in a rectangular cell are studied.The horizontal cross-sectional size of the liquid cell is 52mm × 42mm, the liquid pool is filled with a liquid layer thickness of 3.5mm 1000. During the experiment the temperature difference between the two ends of the liquid pool gradually increased, the fluid flow in the liquid layer gradually changed from stable convection to unstable state.In the experiment The Michelson optical interferometry technology and image processing technology combine to develop a real-time diagnosis of fluid surface morphology of the experimental measurement system.Finally, the Fourier transform method is used to calculate and analyze the laser fringe fringe pattern, and the fluid surface deformation and surface The experimental results show that during the development of hot capillary convection, the surface deformation of the fluid occurs first, and after the temperature difference between the two ends of the liquid pool reaches a certain value, on the basis of this deformation, there will be surface wave information Superimposed on it, the surface deformation and surface waves and fluid temperature gradient, surface tension has a direct relationship; surface wave hidden in the surface Within the deformation.