Pinning and Avalanches in Hydrophobic Microchannels
Pinning and Avalanches in Hydrophobic Microchannels
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DOI：
10.1103/physrevlett.106.194501
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发表时间：
2011-05-10
影响因子：
8.6
通讯作者：
Hernandez-Machado, A.
中科院分区：
文献类型：
--
作者：
Queralt-Martin, M.;Pradas, M.;Hernandez-Machado, A.
罕见事件出现在多种现象中，例如降雨、洪水、地震和风险。我们证明，标准微通道中存在的自然粗糙化引起的随机行为非常重要，以至于水锋推进置换空气的动力学存在大量罕见事件。我们观察到，对于低压差，水前沿与微通道壁的疏水相互作用使前沿接近钉扎点。这会导致爆发式动力学，其特征是一系列钉扎和雪崩，从而导致速度波动的极值甘贝尔分布和平均前沿位置前进的非经典时间指数低至 0.38。
Rare events appear in a wide variety of phenomena such as rainfall, floods, earthquakes, and risk. We demonstrate that the stochastic behavior induced by the natural roughening present in standard microchannels is so important that the dynamics for the advancement of a water front displacing air has plenty of rare events. We observe that for low pressure differences the hydrophobic interactions of the water front with the walls of the microchannel put the front close to the pinning point. This causes a burstlike dynamics, characterized by series of pinning and avalanches, that leads to an extreme-value Gumbel distribution for the velocity fluctuations and a nonclassical time exponent for the advancement of the mean front position as low as 0.38.