基于兰姆波在倾斜玻璃板上推动液滴运动研究

A model for the numerical simulation of the movement of liquid droplets excited by Lamb waves propagating on a 1 mm thick inclined glass plate was developed, and the results of simulation calculations based on this model were compared with experimental observations. In the experiments anti-symmetrical zero order Lamb waves with 1 MHz center frequency were excited on a 1 mm thick glass substrate by piezoelectric single phase transducers, which caused the propulsion of micro-liter water droplets. The acoustic streaming within the droplet was calculated by solving the incompressible Navier-Stokes equations with an inhomogeneous acoustic streaming force field. These calculations were validated by optical measurements of the streaming effects in the droplet and by measurements of the displacement amplitudes of the Lamb waves with a laser-Doppler-vibrometer. Another part of the numerical simulations was related to the transient motion of acoustically driven droplets by solving the incompressible Navier-Stokes equations using the moving mesh application mode of the COMSOL software including a weak formulation for the calculation of the surface tension. The corresponding measurements with a high-speed camera revealed a silkworm-like movement of the droplet resulting from the interaction with acoustic force, surface tension, gravity, and inertial force, which was reproduced by the numerical simulations.

汽车雨刷影响汽车空气阻力系数大小和驾驶员视野，并使驾驶员产生视觉疲劳，如何利用兰姆波模式转换替代汽车雨刷是汽车领域面临的一个国际难题。本项目基于兰姆波波速和衰减值的数据计算、兰姆波激发频率的确定及兰姆波波幅的采集，计算声流力，并基于Weak formulation计算液滴表面张力，通过Moving Mesh 建立基于兰姆波在1毫米斜面玻璃上推动液滴运动数学模型。搭建实验装置，利用压电陶瓷在玻璃基板上激发兰姆波，寻找确定兰姆波最佳激发频率并测量波幅大小，并测量在不同角度斜面玻璃基板上液滴运动实时距离，对比模型计算结果与实验观察数据，以此验证理论模型。项目研究成果可为兰姆波技术代替汽车雨刷同理论和技术支持，对提高驾驶安全具有重要意义。

汽车雨刷影响汽车空气阻力系数大小和驾驶员视野，并使驾驶员产生视觉疲劳，如何利用兰姆波模式转换替代汽车雨刷是汽车领域面临的一个国际难题。本项目基于兰姆波波速和衰减值的数据计算、兰姆波激发频率的确定及兰姆波波幅的采集，计算声流力，并基于Weak formulation计算液滴表面张力，通过Moving Mesh 建立了基于兰姆波在1毫米斜面玻璃上推动液滴运动数学模型。搭建实验装置，利用压电陶瓷在玻璃基板上激发兰姆波，寻找确定了兰姆波最佳激发频率在980kHz~1021kHz，并测量了波幅大小，以及测量了在不同角度斜面玻璃基板上液滴运动实时距离，对比模型计算结果与实验观察数据，以此验证了理论模型。项目研究成果可为兰姆波技术代替汽车雨刷同理论和技术支持，对提高驾驶安全具有重要意义。