振荡“星形”水滴的实验研究

Experimental study on the oscillation-star-like water droplet

对2017年IYPT题目"莱顿弗罗斯特星星"进行了实验研究,发现在外加周期性激励下,温度超过液体莱顿弗罗斯特点的热表面可以让其上的水滴振荡出不同模式的星形图样.根据实验结果,在理论上给出了星形的棱角数与振荡频率的线性近似公式,直观地反映出在激励频率一定时,水滴振荡的棱角数与水滴半径的线性关系.实验还发现莱顿弗罗斯特效应并非是形成振荡星形的必要条件,利用常温的疏水表面也实现了不同振荡模式的星星,而且疏水程度越高的表面激发出星星的棱角越尖锐.

The Leidenfrost star problem in 2017 IYPT was studied experimentally.It was found that in periodic excitation conditions,when the temperature of the hot surface exceeded the Leidenfrost point of the liquid,the water droplets could form different modes of oscillation stars.According to the experimental results,the linear approximation formula about the modes and frequency of the stars was deduced,and the linear relationship between the modes and sizes of the stars was given when the excitation frequency was constant.It was also pointed out that the Leidenfrost effect was not a necessary condition for the appearance of the oscillation stars,different oscillation modes of the stars could also be achieved at room temperature by taking use of hydrophobic surfaces.The experiments with hydrophobic surfaces indicated that the higher the degree of hydrophobicity,the sharper the edges and corners of the stars.