A recent paper reported capillary rise and evaporation experiments in metallic wicks, as well as a mathematical model. The authors found a consistent discrepancy between the model predictions and data: The model over-predicted the capillary height rise by about 20%. The model used assumes that the porous medium is either fully wet or dry, an assumption that is particularly unsuited to evaporati...

Electrowetting generates flow patterns inside drops when AC voltages are employed. For AC frequencies around the drop eigenfrequency (typically O(1kHz) or less), capillary waves emanate from the contact line giving rise to a net motion in the bulk of the drop. This flow can be described by a capillary wave-driven Stokes drift. At higher AC frequencies (above 10kHz, depending on liquid conductiv...

The behaviour of passive tracer particles in capillary Poiseuille flow is investigated with regard to the residence time in short axial sections of length z , in which z /a < Va/D, where a is the capillary radius, V is the mean velocity and D the coefficient of molecular diffusion. While methods exist for calculating moments of the crosssectionally averaged axial concentration distribution as a...

We describe the use of a capillary rise method to measure the wettability of 10 samples of agricultural soil from Rothamsted long-term experimental sites. The samples have very similar clay contents, but organic carbon (C) contents range from 11.5 to 31.2 g kg . Their wetting rates were interpreted by an improved method of data analysis, consistent with the Washburn equation, and showed an incr...

We study the spontaneous formation of granular towers produced when dry sand is poured on a wet sand bed. When the liquid content of the bed exceeds a threshold value W*, the impacting grains have a nonzero probability to stick on the wet grains due to instantaneous liquid bridges created during the impact. The trapped grains become wet by the capillary ascension of water and the process contin...

in this paper, a very efficient method, called single matrix block analyzer (smba), has been developed to determine relative permeability and capillary pressure curves from spontaneous imbibition (si) data. smba mimics realistically the si tests by appropriate boundary conditions modeling. in the proposed method, a cuboid with an identical core plug height is considered. the equal dimensions of...

Polymer nanocomposite films (PNCFs) with extremely high concentrations of nanoparticles are important components in energy storage and conversion devices and also find use as protective coatings in various applications. PNCFs with high loadings of nanoparticles, however, are difficult to prepare because of the poor processability of polymer-nanoparticle mixtures with high concentrations of nano...