论文标题
振动无孔滴的方向运动：一项定量研究
Directional motion of vibrated sessile drops : a quantitative study
论文作者
论文摘要
无柄滴的定向运动可以通过底物的倾斜机械振动来诱导。如前所述，\ cite {brunet07，brunet09，noblin09}，机械振动会诱导结合轴对称和反对称模式的降液变形。在本文中，我们从在大量参数中进行的实验建立了定量趋势，即强迫的振幅$ a $和频率$ f $，液体粘度$η$以及基板和强迫轴$α$之间的角度。这些实验是在弱提取底物上进行的。对于大多数参数集，平均速度$ <v> $用$ a $线性增长。我们提取移动性，定义为$ s = \ frac {Δ<v>} {ΔA} $。发现$ s $可以显示出接近第一个轴对称模式$ f_p $的共振频率的最大值。 $ s $的值几乎是独立的，$η$低于50 CST，而$ s $则显着降低了$η$。此外，发现对于特殊的参数集，尤其是$ f $远远与$ f_p $足够远的情况下，下降的移动朝着反向方向移动。最后，我们在一个振荡的一个时期内，$ <v> $与动态接触角的平均值之间的关系。
The directional motion of sessile drops can be induced by slanted mechanical vibrations of the substrate. As previously evidenced \cite{Brunet07,Brunet09,Noblin09}, the mechanical vibrations induce drop deformations which combine axisymmetric and antisymmetric modes. In this paper, we establish quantitative trends from experiments conducted within a large range of parameters, namely the amplitude $A$ and frequency $f$ of the forcing, the liquid viscosity $η$ and the angle between the substrate and the forcing axis $α$. These experiments are carried out on weak-pinning substrates. For most parameters sets, the averaged velocity $<v>$ grows linearly with $A$. We extract the mobility, defined as $s=\frac{Δ<v>}{ΔA}$. It is found that $s$ can show a sharp maximal value close to the resonance frequency of the first axisymmetric mode $f_p$. The value of $s$ tends to be almost independent on $η$ below 50 cSt, while $s$ decreases significantly for higher $η$. Also, it is found that for peculiar sets of parameters, particularly with $f$ far enough from $f_p$, the drop moves in the reverse direction. Finally, we draw a relationship between $<v>$ and the averaged values of the dynamical contact angles at both sides of the drop over one period of oscillation.
