激光衍射法测量液体的表面波速度和表面张力

Measuring velocity of liquid surface wave and surface tension by laser diffraction

实验上实现了低频液体表面波的激光衍射,提出了激光衍射法测量几百赫兹液体表面波的相速度、群速度和液体的表面张力。当激光斜入射到几百赫兹的液体表面波上,反射的激光产生稳定、清晰的衍射光斑,理论上导出了衍射光斑的角宽度与液体表面波速度的解析关系,实验上测得几百赫兹液体表面波的相速度和群速度,并测量了液体的表面张力。根据其机理,建立起一种实时、非接触的测量液体表面波的相速度、群速度和表面张力的实用方法。

Light diffraction from liquid surface wave at low - frequency was experimentally realized, a laser diffraction technique for measuring phase velocity, group velocity and surface tension of liquid wave was designed. When laser falls on the liquid surface wave of several hundreds in angle, in the experiment steady and visible diffraction patterns were obtained. The analytic expression of the angle width of the diffraction fringe range and velocity of surface waves was derived theoretically, subsequently, measuring the phase velocity, the group velocity and surface tension in the experiment. Based on the principle of this experiment, a practical technique, can be developed to measurephase velocity, group velocity of surface waves and surface tension in a real time and non - contact way.