Dynamics of drop impact onto a solid sphere: spreading and retraction
Dynamics of drop impact onto a solid sphere: spreading and retraction
复制标题
水滴撞击固体球体的动力学：扩散和收缩
DOI：
10.1017/jfm.2017.388
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发表时间：
2017-07
影响因子：
3.7
通讯作者：
Lu Xi Yun
中科院分区：
文献类型：
--
作者：
Zhu Yang;Liu Hao Ran;Mu Kai;Gao Peng;Ding Hang;Lu Xi Yun
本文用数值方法研究了中等雷诺数和韦伯数下的球落冲击问题。很自然地，球体与液滴的纵横比$\unicode[STIX]{x1D706}_{r}$与液滴撞击平坦基底相比，会对液滴在球体上的扩散和收缩产生很大的影响。为了定量评价$\unicode[STIX]{x1D706}_{r}$的效果，通过实验验证，采用了扩散界面浸没边界法。借助数值模拟，我们确定了扩散和收缩的关键机制，利用标度律分析了结果，并定量评价了$\unicode[STIX]{x1D706}_{r}$对冲击动力学的影响。我们发现，在球体上扩散的液膜厚度可以很好地近似为$h_{L,\infty }(1+3/4\unicode[STIX]{x1D706}_{r}^{-3/2})$，其中$h_{L,\infty }$表示液滴冲击在平面基底上的膜厚度。在扩散初期，以液膜厚度重新标度时间时，浸润面积的时间变化与$\unicode[STIX]{x1D706}_{r}$无关。观察到液滴在球上以大致恒定的速度缩回，理论分析的预测与数值结果吻合较好。
In this paper, drop impact onto a sphere is numerically investigated at moderate Reynolds and Weber numbers. It is naturally expected that the aspect ratio of the sphere to the drop, $\unicode[STIX]{x1D706}_{r}$ , would make a big difference to drop spreading and retraction on the sphere, compared with drop impact onto a flat substrate. To quantitatively assess the effect of $\unicode[STIX]{x1D706}_{r}$ , a diffuse-interface immersed-boundary method is adopted after being validated against experiments. With the help of numerical simulations, we identify the key regimes in the spreading and retraction, analyse the results by scaling laws, and quantitatively evaluate the effect of $\unicode[STIX]{x1D706}_{r}$ on the impact dynamics. We find that the thickness of the liquid film spreading on the sphere can be well approximated by $h_{L,\infty }(1+3/4\unicode[STIX]{x1D706}_{r}^{-3/2})$ , where $h_{L,\infty }$ represents the film thickness of drop impact on a flat substrate. At the early stage of spreading, the temporal variation of the wetted area is independent of $\unicode[STIX]{x1D706}_{r}$ when the time is rescaled by the thickness of the liquid film. Drops are observed to retract on the sphere at a roughly constant speed, and the predictions of theoretical analysis are in good agreement with numerical results.
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影响因子：
16.6
作者：
Liu Y;Andrew M;Li J;Yeomans JM;Wang Z
通讯作者：
Wang Z
影响因子：
4.6
作者：
Kim, HY;Feng, ZC;Chun, JH
通讯作者：
Chun, JH
DOI：
10.1209/0295-5075/106/24001
发表时间：
2014-03
期刊：
Europhysics Letters
影响因子：
--
作者：
C. S. Stevens
通讯作者：
C. S. Stevens
影响因子：
4.6
作者：
Bakshi, Shamit;Roisman, Ilia V.;Tropea, Cam
通讯作者：
Tropea, Cam
影响因子：
4.6
作者：
A. Rozhkov;B. Prunet-Foch;M. Vignes-Adler
通讯作者：
A. Rozhkov;B. Prunet-Foch;M. Vignes-Adler