Experimental determination of forces applied by liquid water drops at high drop velocities impacting a glass plate with and without a shallow water layer using wavelet deconvolution
Experimental determination of forces applied by liquid water drops at high drop velocities impacting a glass plate with and without a shallow water layer using wavelet deconvolution
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DOI：
10.1007/s00348-018-2537-9
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发表时间：
2018-04
影响因子：
2.4
通讯作者：
Y. Yu;C. Hopkins
中科院分区：
文献类型：
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作者：
Y. Yu;C. Hopkins
用力传导法和小波反褶积两种不同的方法测量了直径为2 mm和4.5 mm的水滴(速度最高可达终端速度)撞击有或无水层(深度达10 mm)的玻璃板所施加的随时间变化的力。对于落在干玻璃上的水滴，这两种方法都非常一致。然而，只有小波方法能够测量浅水层上的飞溅的自然特征，这些飞溅在初始撞击后向板块施加力。在相对较高的速度(包括末端速度)下，从初始撞击测得的峰值力明显高于理想化的液滴形状模型和Roisman等人的模型所预测的峰值。和Marengo等人。因此，建立了液滴以不同速度落到干玻璃表面的初始随时间变化的冲击力的经验公式，(B)落入有水层的干玻璃或有水层的玻璃的最终速度，以及(C)低于最终速度的不同速度落到有水层的干玻璃或有水层的玻璃上的初始冲击力。对于干玻璃上的水滴，经验公式适用于玻璃板或具有玻璃表面的复合材料层合板，尽管它们适用于其他板厚度，并适用于具有类似表面粗糙度和润湿性的任何板材料。测量还表明，在最初的撞击之后，当气泡夹带在水层中时，可能会有高水平的力。
Time-dependent forces applied by 2 and 4.5 mm diameter drops of water (with velocities up to terminal velocity) impacting upon a glass plate with or without a water layer (up to 10 mm depth) have been measured using two different approaches, force transduction and wavelet deconvolution. Both approaches are in close agreement for drops falling on dry glass. However, only the wavelet approach is able to measure natural features of the splash on shallow water layers that impart forces to the plate after the initial impact. At relatively high velocities (including terminal velocity) the measured peak force from the initial impact is significantly higher than that predicted by idealised drop shape models and models from Roisman et al. and Marengo et al. Hence empirical formulae are developed for the initial time-dependent impact force from drops falling at (a) different velocities up to and including terminal velocity onto a dry glass surface, (b) terminal velocity onto dry glass or glass with a water layer and (c) different velocities below terminal velocity onto dry glass or glass with a water layer. For drops on dry glass, the empirical formulae are applicable to a glass plate or a composite layered plate with a glass surface, although they apply to other plate thicknesses and are applicable to any plate material with a similar surface roughness and wettability. The measurements also indicate that after the initial impact there can be high level forces when bubbles are entrained in the water layer.