The Surface Tension Of Light Caused By Vacuolar Dynamics Characteristics Of The Experimental Study

Surface tension effects on the growth and collapse of a cavitation bubble and the mechanical effects near a rigid boundary was investigated by a fiber-optic diagnostic technique based on optical beam deflection (OBD). In the experimental study, cavitation bubble was induced by focusing the Nd:YAG laser into the vessel containing liquids with different surface tension, the expansion and collapse of bubble and the normal force acting on the surface were investigated by a sensitive fiber-optic sensor. The effect of surface tension on cavitation oscillation includes bubble radius, the bubble wall velocity, bubble energy. As to the case of mechanical effects, the surface tension has substantial effect on the liquid-jet and bubble collapse duration. Besides, according to experimental results and the modified Rayleigh theory, the maximum bubble radius the liquid-jet pressure and the liquid-jet velocity were obtained and they all changed with the increasing surface tension.The other part of my research is numerical analyses,which was based on Rayleigh-Plesset equation. A finite different method is applied to numerically simulate the effect of surface tension on the entire process of bubble oscillation. These numerical results are consistent with experimental results, which prove the validity of our experimental results.Moreover, via the mechanism of mechanics, the physical phenomenon induced by surface tension effects in the expansion and collapse of bubble was analyzed. As we know surface tension has the tendency to reduce the volume of the cavity. For an initially spherical cavity growing and collapsing near a rigid wall, during the growth phase surface tension will have the effect of stabilizing the deformation of the cavity and make it closer to a spherical shape, and during the collapse phase surface tension will have the effect of destabilizing the deformation of the cavity, accelerating the collapse, and thus will have the tendency to strengthen the cavitation erosion effects.These results help to better understand the cavitation erosion and optimize laser parameters in the fields of laser ophthalmology and underwater laser processing.