Experimental analysis of the interaction of adhering droplets for different arrangement of droplets under the influence of flow and surface vibration

由于接触角滞后的影响，液滴可以粘附在表面上，直到达到气流的临界速度（例如，头盔面罩上的液滴）。如果表面的振动被叠加，则可以观察到临界速度的减小，导致在流动方向上的运输。如果存在一个以上的液滴，则可以观察到液滴的聚结，从而产生液膜。液滴的分离和膜的产生是以下因素的函数：（i）液滴的排列，（ii）表面振动的频率和振幅，（iii）液滴体积，（iv）液体性质和（v）润湿行为（表面张力、接触角）。对于不同排列的液滴，应检查这种关系。这应该以实验性的方法进行。对于实验，使用连接到电磁振动器以产生受控表面振动的流动通道。液滴运动的评估和分析是通过光学方法（阴影和PIV）完成的。

Because of the effects of contact angle hysteresis, droplets can stick to surfaces until a critical velocity of the gas flow is reached (e.g. droplet on the visor of a helmet). If a vibration of the surface is superposed, a reduction of the critical velocity can be observed leading to a transport in flow direction. If more than one droplet is present, coalescence of the droplets can be observed leading to the creation of liquid films. The detachment of droplets and the creation of films is a function of (i) the arrangement of the droplets, (ii) frequency and amplitude of the surface vibration, (iii) droplet volumina, (iv) liquid properties and (v) wetting behaviour (surface tension, contact angles). The relation should be examined for droplets in different arrangements. This should be done in an experimental approach. For the experiments flow channels are used which are connected to an electromagnetic shaker to generate controlled surface vibrations. The evaluation and analysis of the droplet movement is done by optical methods (shadowgraphy and PIV).