Infiltration and dimensional scaling of inkjet droplets on thick isotropic porous materials

Oko, Asaf; Martinez, D. Mark; Swerin, Agne

doi:10.1007/s10404-013-1313-7

Cited by 16 publications

(28 citation statements)

References 32 publications

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“…The time exponent obtained empirically by Oko et al . () was z = 0.8. That result used only data obtained after a particular value of t , and is similar to the time exponent for our data following the inertial‐viscous transition.…”

Section: Resultsmentioning

confidence: 66%

“…This indicates that the data of Oko et al . () probably covered a regime in which inertia did not affect the scaling.…”

Section: Resultsmentioning

confidence: 99%

“…That result used only data obtained after a particular value of t, and is similar to the time exponent for our data following the inertial-viscous transition. This indicates that the data of Oko et al (2014) probably covered a regime in which inertia did not affect the scaling.…”

Section: Static and Dynamic Penetrationmentioning

confidence: 86%

“…When only those data for t > 10 ms were considered, the mean gradient was 0.85 ± 0.08 (from three datasets). The time exponent obtained empirically by Oko et al (2014) was z = 0.8. That result used only data obtained after a particular value of t, and is similar to the time exponent for our data following the inertial-viscous transition.…”

Section: Static and Dynamic Penetrationmentioning

confidence: 90%

“…To analyse imbibition, we used a scaling model of the form V (t) ∝ t z , where t is the time after impact. This scaling is appropriate for droplet uptake into porous materials (Oko et al, 2014) because it is assumed that gravitational effects are negligible and that the dynamics are dominated by capillarity within the porous material. These assumptions were reasonable here because the curvature of the liquid-air interface inside the porous bed was much smaller than that of the drop on the surface.…”

Section: Penetration Experimentsmentioning

confidence: 99%

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High‐speed photography of water drop impacts on sand and soil

Lardier

Roudier

Clothier

et al. 2018

European J Soil Science

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Summary The way that water drops impact on soil is of widespread importance for soil science, particularly in the context of irrigation and erosion. With modern high‐speed photography techniques, impacts on granular materials are becoming more widely studied, but the variation in particle‐size distribution of soil presents particular challenges. Here, the impacts of individual water drops on two contrasting soil textures (pure sand and a loamy soil) have been studied with high‐speed photography, and compared at Weber numbers between 50 and 750. Granular samples with wider distributions of particle sizes produce larger variations in experimental outcomes. For the sand, which contained >98% particles between 60 μm and 2 mm in size, the typical outcome involved spreading and retraction of the drop to a circular profile with a raised rim. The loamy soil had greater surface roughness than the sand, with a wider distribution of particle sizes, so that the spread of the drop was more anisotropic, involved more movement of target particles and often involved droplet breakup into satellite drops. Overall outcomes were best described by a gravity‐dominated cratering mechanism, and the scaling exponent for the crater diameter with respect to impact energy was 0.22 ± 0.03. Dynamic penetration studies enabled visualization of granular motion below the surface, and both static and dynamic penetration results illustrated a transition between inertial and viscous regimes over time. As the water content of the soil was increased, droplet breakup was initially encouraged before capillary imbibition dominated at water contents close to 10%v/v. This research is useful for understanding how rain and irrigation, which comprise many millimetre‐scale drops, influence large‐scale hydraulic properties in soil, including surface sealing. Highlights Drop impact on to soil is important, but its systematic study is difficult because of variation in soil particle sizes. High‐speed photography was used to study drop impacts on to a pure sand and loamy soil, and analysed quantitatively. Results show how granular samples with wider distributions of particle sizes produce more variation in experimental outcomes. The maximum extent of drop spreading was best described by a scaling model developed for planetary cratering.

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Section: Resultsmentioning

confidence: 66%

“…This indicates that the data of Oko et al . () probably covered a regime in which inertia did not affect the scaling.…”

Section: Resultsmentioning

confidence: 99%

Section: Static and Dynamic Penetrationmentioning

confidence: 86%

Section: Static and Dynamic Penetrationmentioning

confidence: 90%

Section: Penetration Experimentsmentioning

confidence: 99%

See 3 more Smart Citations

High‐speed photography of water drop impacts on sand and soil

Lardier

Roudier

Clothier

et al. 2018

European J Soil Science

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Darcy's law for two‐dimensional flows: Singularities at corners and a new class of models

Shikhmurzaev

2017

AIChE Journal

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As is known, Darcy's model for fluid flows in isotropic homogeneous porous media gives rise to singularities in the velocity field for essentially two‐dimensional flow configuration, like flows over corners. Considering this problem from the modeling viewpoint, this study aims at removing this singularity, which cannot be regularized via conventional generalizations of the Darcy model, like Brinkman's equation, without sacrificing Darcy's law itself for unidirectional flows where its validity is well established experimentally. The key idea is that as confirmed by a simple analogy, the permeability of a porous matrix with respect to flow is not a constant independent of the flow but a function of the flow field (its scalar invariants), decreasing as the curvature of the streamlines increases. This introduces a completely new class of models where the flow field and the permeability field are linked and, in particular problems, have to be found simultaneously. © 2017 American Institute of Chemical Engineers AIChE J, 2017

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Absorption of millimeter- and micrometer-sized droplets on nylon powder

Tan

2022

Exp Fluids

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Absorption of droplet by the powder media is a ubiquitous phenomenon in many natural and engineering processes, in which the diameter of droplets ranges from tens of micrometers (μm) to a few millimeters (mm) depending on the speci c condition. In this study, we investigate the absorption process following the impact of the droplet with radii varying from mm-to μm-scale on nylon powder substrate. The uid properties are varied by mixing the deionized water with isopropyl alcohol at different volume ratios. A syringe pipette tip is used to generate droplets of diameter ranging from 2.08 to 2.30 mm, whereas a drop-on-demand inkjet device is used to dispense droplets of diameter ranging from 88 to 140 μm. The absorption process of the single droplet is captured by a high-speed imaging system. We nd that for mm-and μm-droplets there exists different critical surface tension below which the imbibition into the nylon powder can occur. With the proposed nondimensionalization process, the scattered data of dimensionless absorbed volume V and dimensionless time τ for different uids generally collapse into a power law relation V~ τ α , where the exponent α for mm-sized and μm-sized droplets is 0.856 and 0.518, respectively. The experimental data of μm droplets generally agree with the prediction of the Washburn equation for the unidirectional capillary ow, i.e. V~ τ 0.5 . However, the results of mm-droplets favor more the prediction of the 3D radial ow (i.e., a hemispherically advancing in ltration front inside the powder), V~ τ.

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Infiltration and dimensional scaling of inkjet droplets on thick isotropic porous materials

Cited by 16 publications

References 32 publications

High‐speed photography of water drop impacts on sand and soil

High‐speed photography of water drop impacts on sand and soil

Darcy's law for two‐dimensional flows: Singularities at corners and a new class of models

Absorption of millimeter- and micrometer-sized droplets on nylon powder

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