Journal articles: 'Wetting ridge'

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Park, S. J., J. B. Bostwick, V. De Andrade, and J. H. Je. "Self-spreading of the wetting ridge during stick-slip on a viscoelastic surface." Soft Matter 13, no. 44 (2017): 8331–36. http://dx.doi.org/10.1039/c7sm01408b.

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Annakodi, Vivek Anand, Ramachandra Arvind Singh, Subramanian Jayalakshmi, Yupeng Zhang, Koppula Srinivas Rao, and Rajashekhara Shabadi. "Anticorrosion Behaviour of SS304 Microgroove Surfaces in Saline Water." Metals 11, no. 10 (September 28, 2021): 1543. http://dx.doi.org/10.3390/met11101543.

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The 304 Stainless Steel (SS304) is severely affected by salt water corrosion due to its high surface wettability. By reducing its surface wettability, its corrosion can be reduced. To achieve this, topographical modification of the steel surface is an effective route. In this work, SS304 flat surfaces were topographically modified into microgrooves (ridge width 250 μm to 500 μm, groove width 200 μm, width ratio = ridge width/groove width >1). Wire cut electrical discharge machining was used to fabricate the microgrooves. Long-term wetting characteristics and long-term corrosion behaviour of flat surface and microgrooves were studied. The influence of the nature of wetting of the tested surfaces on their corrosion behaviour was examined. The sessile drop method and potentiodynamic polarization tests in sodium chloride (3.5 wt. % NaCl) solution (intermittent and continuous exposures for 168 h) were studied to characterize their wetting and corrosion behaviours, respectively. Topographical modification imparted long-term hydrophobicity and, as a consequence, long-term anticorrosion ability of the steel surface. Micropatterning reduced the corrosion rate by two orders of magnitude due to reduction in interfacial contact area with the corrosive fluid via composite wetting, i.e., solid–liquid–air interface. Microgrooves showed corrosion inhibition efficiency ≥88%, upon long-term exposure to NaCl solution. By comparing the wetting and corrosion behaviours of the microgrooves with those of the previously studied microgrooves (ridge width/groove width <1), it was found that the surface roughness of their ridges strongly influences their wetting and corrosion properties.

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Кошоридзе, С. И. "Влияние диссипации энергии в подложке на время жизни поверхностных нанопузырьков." Письма в журнал технической физики 49, no. 1 (2023): 14. http://dx.doi.org/10.21883/pjtf.2023.01.54050.19357.

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Based on the analogy between the process of spreading a liquid droplet on a hydrophobic surface and the diffusion dissolution of surface nanobubbles (SNB), the shape of the wetting ridge, deformed by capillary forces of the substrate surface area adjacent to the contact line of the three phases, is calculated within the framework of linear elasticity theory. It is shown that the energy dissipation in viscoelastic substrates on the wetting ridge can cause the pinning of the triple line and the termination of the diffusion dissolution of the SNB.

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Heyden, Stefanie, Nicolas Bain, Qin Xu, Robert W. Style, and Eric R. Dufresne. "Contact lines on stretched soft solids: modelling anisotropic surface stresses." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 477, no. 2245 (January 2021): 20200673. http://dx.doi.org/10.1098/rspa.2020.0673.

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We present fully analytical solutions for the deformation of a stretched soft substrate due to the static wetting of a large liquid droplet, and compare our solutions to recently published experiments (Xu et al. 2018 Soft Matter 14, 916–920 (doi:10.1039/C7SM02431B)). Following a Green’s function approach, we extend the surface-stress regularized Flamant–Cerruti problem to account for uniaxial pre-strains of the substrate. Surface profiles, including the heights and opening angles of wetting ridges, are provided for linearized and finite kinematics. We fit experimental wetting ridge shapes as a function of applied strain using two free parameters, the surface Lamé coefficients. In comparison with experiments, we find that observed opening angles are more accurately captured using finite kinematics, especially with increasing levels of applied pre-strain. These fits qualitatively agree with the results of Xu et al ., but revise values of the surface elastic constants.

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Carre, A., and M. E. R. Shanahan. "Influence of the "Wetting Ridge" in Dry Patch Formation." Langmuir 11, no. 9 (September 1995): 3572–75. http://dx.doi.org/10.1021/la00009a047.

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Semprebon, Ciro, Glen McHale, and Halim Kusumaatmaja. "Apparent contact angle and contact angle hysteresis on liquid infused surfaces." Soft Matter 13, no. 1 (2017): 101–10. http://dx.doi.org/10.1039/c6sm00920d.

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Choi, Jung Won, Daseul Ham, Seonghyun Han, Do Young Noh, and Hyon Chol Kang. "Nanoscale Soft Wetting Observed in Co/Sapphire during Pulsed Laser Irradiation." Nanomaterials 11, no. 2 (January 20, 2021): 268. http://dx.doi.org/10.3390/nano11020268.

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Liquid drops on deformable soft substrates exhibit quite complicated wetting behavior as compared to those on rigid solid substrates. We report on a soft wetting behavior of Co nanoparticles (NPs) on a sapphire substrate during pulsed laser-induced dewetting (PLID). Co NPs produced by PLID wetted the sapphire substrate with a contact angle near 70°, which is in contrast to typical dewetting behavior of metal thin films exhibiting contact angles greater than 90°. In addition, a nanoscale γ-Al2O3 wetting ridge about 15 nm in size and a thin amorphous Al2O3 interlayer were observed around and beneath the Co NP, respectively. The observed soft wetting behavior strongly indicates that the sapphire substrate became soft and deformable during PLID. Moreover, the soft wetting was augmented under PLID in air due to the formation of a CoO shell, resulting in a smaller contact angle near 30°.

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Rashidian, Hossein, Matheu Broom, Geoff R. Willmott, and Mathieu Sellier. "Eﬀects of a microscale ridge on dynamic wetting during drop impact." Journal of the Royal Society of New Zealand 50, no. 4 (January 22, 2020): 523–37. http://dx.doi.org/10.1080/03036758.2019.1706587.

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Surapaneni, Venkata A., Georg Bold, Thomas Speck, and Marc Thielen. "Spatio-temporal development of cuticular ridges on leaf surfaces of Hevea brasiliensis alters insect attachment." Royal Society Open Science 7, no. 11 (November 2020): 201319. http://dx.doi.org/10.1098/rsos.201319.

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Cuticular ridges on plant surfaces can control insect adhesion and wetting behaviour and might also offer stability to underlying cells during growth. The growth of the plant cuticle and its underlying cells possibly results in changes in the morphology of cuticular ridges and may also affect their function. We present spatial and temporal patterns in cuticular ridge development on the leaf surfaces of the model plant, Hevea brasiliensis . We have identified, by confocal laser scanning microscopy of polymer leaf replicas, an acropetally directed progression of ridges during the ontogeny of Hevea brasiliensis leaf surfaces. The use of Colorado potato beetles (Leptinotarsa decemlineata) as a model insect species has shown that the changing dimensions of cuticular ridges on plant leaves during ontogeny have a significant impact on insect traction forces and act as an effective indirect defence mechanism. The traction forces of walking insects are significantly lower on mature leaf surfaces compared with young leaf surfaces. The measured walking traction forces exhibit a strong negative correlation with the dimensions of the cuticular ridges.

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Kim, T. H., J. Seo, J. Choi, B. Y. Choi, Y. J. Song, Y. Kuk, and S. J. Kahng. "Strain-relieving ridge structure in a wetting layer on the W(110) surface." Surface Science 595, no. 1-3 (December 2005): 30–34. http://dx.doi.org/10.1016/j.susc.2005.07.034.

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11

Pu, Gang, Jihui Guo, Larry E. Gwin, and Steven J. Severtson. "Mechanical Pinning of Liquids through Inelastic Wetting Ridge Formation on Thermally Stripped Acrylic Polymers." Langmuir 23, no. 24 (November 2007): 12142–46. http://dx.doi.org/10.1021/la701652m.

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Alves Júnior, José, Wije Mallikaara Bandaranayake, and James Syvertsen. "DRIP IRRIGATION WETTING PATTERNS IN A MID FLORIDA SANDY SOIL." IRRIGA 1, no. 01 (June 18, 2018): 1. http://dx.doi.org/10.15809/irriga.2016v1n01p1-25.

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DRIP IRRIGATION WETTING PATTERNS IN A MID FLORIDA SANDY SOIL JOSÉ ALVES JÚNIOR1; WIJE MALLIKAARACHCHIGE BANDARANAYAKE2 E JAMES SYVERTSEN2 1Eng. Agr. Professor Adjunto da Escola de Agronomia (EA) da Universidade Federal de Goiás (UFG), Avenida Esperança, s/n, Campus Samambaia, Goiânia, Goiás, Brasil, CEP: 74.690-900. jose.junior@pq.cnpq.br2Professor and Researcher in University of Florida, IFAS, CREC, Lake Alfred-FL 33850, USA. wijeb@ufl.edu, jmsn@ufl.edu 1 ABSTRACT The wetting pattern of soil under drip irrigation is governed by soil texture, structure, initial water content, emitter spacing, discharge rate and irrigation frequency. Although drip irrigation is not common in central Florida “Ridge soils”, the “advanced citrus production system” can hold a promising future. High frequency, short duration pulses is an important factor to consider for efficient irrigation in this very sandy “Ridge” soils. The objective of this research was to evaluate the water distribution pattern under 1.9, 4.6 and 8.6 L h-1 discharge rate drippers over different wetting durations using three evaluation methods: a) EC5 soil water sensors, b) blue dye tracer, and c) a simple mathematical model developed for sandy soils. Of the three methods, the dye method is labor intensive and time consuming and was used only to evaluate one pulse rate with 3 pulse durations. Soil water sensors, though relatively expensive, gave the most detailed wetting patterns under different combinations of pulse rates and wetting durations. The model overestimated the wetting depth and underestimated the wetting diameter. With the initial soil moisture at 0.055 m3 m-3 and a constant application pressure of 138 kPa, the maximum achievable wetting diameter with increasing pulse rate and pulse duration was limited to 0.75 m. However, the wetting depth increased >1 m with >4.63 L h-1 pulse rate and 3-h duration. Preferential flow was minimal but had little influence on wetting pattern. The best combination was the 4.63 L h-1 emitter with a 3 h pulse that yielded the maximum wetting diameter (0.77 m) and the optimum wetting depth (0.77 m). Keywords: Trickle irrigation, soil water sensors, FD&CC blue dye, soil water movement, water use efficiency. ALVES JÚNIOR., J.; BANDARANAYAKE, W. M.; SYVERTSEN, J. BULBO MOLHADO SOB IRRIGAÇÃO POR GOTEJAMENTO EM SOLO ARENOSO NA FLORIDA 2 RESUMO O padrão de umedecimento do solo sob irrigação por gotejamento é regido pela textura do solo, a estrutura, o conteúdo inicial de água solo, espaçamento entre emissores, a vazão do emissor e freqüência de irrigação. Embora, a irrigação por gotejamento não seja comum no centro da Flórida, no "sistema avançado de produção de citros" pode conter um futuro promissor. Alta freqüência, pulsos de curta duração é um fator importante a considerar para irrigação eficiente neste solo arenoso. O objetivo deste trabalho foi avaliar o padrão de distribuição de água em diferentes vazões de gotejadores 1,9, 4,6 e 8,6 L h-1 ao longo de diferentes períodos de molhamento usando três métodos de avaliação : a) sensores de água no solo EC5 , b) corante azul , e c) um modelo matemático simples. Dos três métodos, o método do corante é trabalhoso e consome muito tempo, e por isso só foi utilizado para avaliar uma vazão em 3 diferentes tempos de irrigação. Sensores de água no solo, apesar de relativamente caro, deu os padrões de molhamento mais detalhados sob diferentes combinações de vazão e tempo de irrigação. O modelo superestimou a profundidade molhada e subestimou o diâmetro molhado. Com a umidade do solo inicial de 0,055 m3 m-3 e uma pressão de aplicação constante de 138 kPa, o diâmetro molhado máximo obtido entre as vazões e tempos de irrigação avaliados foi de 0,75 m. No entanto, profundidade molhada ultrapassa 1 m, com 4,63 L h-1 de vazão do gotejador e 3 h de tempo de irrigação. Fluxo preferencial foi mínimo, mas teve pouca influência sobre o bulbo molhado. A melhor combinação foi a vazão de 4,63 Lh-1 com um tempo de 3 h, que produziu o diâmetro máximo de molhagem (0,77 m) e a profundidade de molhagem óptima (0,77 m). Palavras-Chave: Irrigação localizada; sensors de água no solo; FD&CC blue dye; movimento de água no solo

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Hernández Sánchez, Jazmin Maria de los Dolores, Demetrio S. Fernández Reynoso, Mario R. Martínez Menez, Benjamín Figueroa Sandoval, Erasmo Rubio Granados, and José Luis García Rodríguez. "Evaluación de la estabilidad de taludes en cárcavas, Huasca de Ocampo, Hidalgo, México." REVISTA TERRA LATINOAMERICANA 37, no. 3 (July 15, 2019): 303. http://dx.doi.org/10.28940/terra.v37i3.468.

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In Santo Domingo, Huasca de Ocampo, Hidalgo, changes in the use of soil, the topographic and geomorphological conditions and the increase of runoffs, promote the formation of gullies in agricultural areas, causing the loss of soil fertility and a reduction of agricultural land. The objective of our research was to identify the main topographic features and physical/mechanical properties of the soil that cause a sidewall retreat of gullies (AV); determination was performed through principal component analysis (PCA) and multiple linear regression (MLR). The AV varied from 0.04 to 0.17 m yr‑1 with a mean value of 0.092 m yr-1. The most important variables in the PCA were: height, slope, orientation, vertical and horizontal curvature, transversal slope, ridge thickness, bulk density (0 to 5 and 5 to 10 cm), penetration resistance (2.5, 5 and 10 cm), hydraulic conductivity, shrinkage index, plasticity index, 0.25, 0.15 and 0.075 mm particles, cohesion and soil erodibility factor. The best linear regression explanatory model presented a f it value of 84.02% using four variables (particles of 0.15 and 0.075 mm, slope and ridge thickness). The AV is influenced by the presence of silt and clay in the regolith and soil surface (ridge), which are vulnerable to wetting and drying processes that boost the formation of cracks and disaggregation of the components of ridge and slope, reducing the soil’s resistance to erosion and causing headward erosion and instability in the gully slopes.

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14

GOMBA, J. M., and G. M. HOMSY. "Regimes of thermocapillary migration of droplets under partial wetting conditions." Journal of Fluid Mechanics 647 (March 18, 2010): 125–42. http://dx.doi.org/10.1017/s0022112010000078.

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We study the thermocapillary migration of two-dimensional droplets of partially wetting liquids on a non-uniform heated substrate. An equation for the thickness profile of the droplet is derived by employing lubrication approximations. The model includes the effect of a non-zero contact angle introduced through a disjoining–conjoining pressure term. Instead of assuming a fixed shape for the droplet, as in previous works, here we allow the droplet to change its profile with time. We identify and describe three different regimes of behaviour. For small contact angles, the droplet spreads into a long film profile with a capillary ridge near the leading edge, a behaviour that resembles the experiments on Marangoni films reported by Ludviksson & Lightfoot (Am. Inst. Chem. Eng. J., vol. 17, 1971, pp. 1166). For large contact angles, the droplet moves as a single entity, weakly distorted from its static shape. This regime is the usual one reported in experiments on thermocapillary migration of droplets. We also show some intriguing morphologies that appear in the transition between these two regimes. The occurrence of these three regimes and their dependence on various parameters is analysed.

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Roy, Rishav, Robert L. Seiler, Justin A. Weibel, and Suresh V. Garimella. "Droplets on Soft Surfaces Exhibit a Reluctance to Coalesce due to an Intervening Wetting Ridge." Advanced Materials Interfaces 7, no. 17 (July 12, 2020): 2000731. http://dx.doi.org/10.1002/admi.202000731.

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HOSOI, A. E., and JOHN W. M. BUSH. "Evaporative instabilities in climbing films." Journal of Fluid Mechanics 442 (August 24, 2001): 217–39. http://dx.doi.org/10.1017/s0022112001005018.

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We consider flow in a thin film generated by partially submerging an inclined rigid plate in a reservoir of ethanol– or methanol–water solution and wetting its surface. Evaporation leads to concentration and surface tension gradients that drive flow up the plate. An experimental study indicates that the climbing film is subject to two distinct instabilities. The first is a convective instability characterized by flattened convection rolls aligned in the direction of flow and accompanied by free-surface deformations; in the meniscus region, this instability gives rise to pronounced ridge structures aligned with the mean flow. The second instability, evident when the plate is nearly vertical, takes the form of transverse surface waves propagating up the plate.We demonstrate that the observed longitudinal rolls are driven by the combined influence of surface deformations and alcohol concentration gradients. Guided by the observation that the rolls are flattened, we develop a quasi-two-dimensional theoretical model for the instability of the film, based on lubrication theory, which includes the effects of gravity, capillarity and Marangoni stresses at the surface. We develop stability criteria for the film which are in qualitative agreement with our experimental observations. Our analysis yields an equation for the shape of the interface which is solved numerically and reproduces the salient features of the observed flows, including the slow lateral drift and merging of the ridges.

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Pu, Gang, Jun Ai, and Steven J. Severtson. "Drop Behavior on a Thermally-Stripped Acrylic Polymer: Influence of Surface Tension Induced Wetting Ridge Formation on Retention and Running." Langmuir 26, no. 15 (August 3, 2010): 12696–702. http://dx.doi.org/10.1021/la101786r.

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Gevaert, A. I., A. J. Teuling, R. Uijlenhoet, and P. A. Troch. "Hillslope experiment demonstrates role of convergence during two-step saturation." Hydrology and Earth System Sciences Discussions 11, no. 2 (February 20, 2014): 2211–32. http://dx.doi.org/10.5194/hessd-11-2211-2014.

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Abstract. A continuous and intense rainfall experiment on an artificial hillslope at the Landscape Evolution Observatory in Biosphere 2 resulted in saturation excess overland flow and gully erosion in the convergent hillslope area. An array of 496 soil moisture sensors revealed a two-step saturation process. First, the downward movement of the wetting front brought soils to a relatively constant but still unsaturated moisture content. Second, soils were brought to saturated conditions from below in response to rising water tables. Convergent areas responded faster than upslope areas, due to contributions from lateral subsurface flow. This led to the formation of a groundwater ridge in the convergent area, triggering saturation excess runoff generation. This unique experiment demonstrates, at very high spatial and temporal resolution, the role of convergence on subsurface storage and flow dynamics. The results bring into question the representation of saturation excess overland flow in conceptual rainfall-runoff models and land-surface models, since flow is gravity-driven in many of these models and upper layers cannot become saturated from below.

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An, Juan, and QianJin Liu. "Soil aggregate breakdown in response to wetting rate during the inter-rill and rill stages of erosion in a contour ridge system." CATENA 157 (October 2017): 241–49. http://dx.doi.org/10.1016/j.catena.2017.05.027.

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Roy, Rishav, Robert L. Seiler, Justin A. Weibel, and Suresh V. Garimella. "Soft Surface: Droplets on Soft Surfaces Exhibit a Reluctance to Coalesce due to an Intervening Wetting Ridge (Adv. Mater. Interfaces 17/2020)." Advanced Materials Interfaces 7, no. 17 (September 2020): 2070098. http://dx.doi.org/10.1002/admi.202070098.

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Zhang, Xudong, Ji Zhao, Linchuan Yang, Muhammad Kamran, Xuanke Xue, Zhaoyun Dong, Zhikuan Jia, and Qingfang Han. "Ridge-furrow mulching system regulates diurnal temperature amplitude and wetting-drying alternation behavior in soil to promote maize growth and water use in a semiarid region." Field Crops Research 233 (March 2019): 121–30. http://dx.doi.org/10.1016/j.fcr.2019.01.009.

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Gevaert, A. I., A. J. Teuling, R. Uijlenhoet, S. B. DeLong, T. E. Huxman, L. A. Pangle, D. D. Breshears, et al. "Hillslope-scale experiment demonstrates the role of convergence during two-step saturation." Hydrology and Earth System Sciences 18, no. 9 (September 24, 2014): 3681–92. http://dx.doi.org/10.5194/hess-18-3681-2014.

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Abstract. Subsurface flow and storage dynamics at hillslope scale are difficult to ascertain, often in part due to a lack of sufficient high-resolution measurements and an incomplete understanding of boundary conditions, soil properties, and other environmental aspects. A continuous and extreme rainfall experiment on an artificial hillslope at Biosphere 2's Landscape Evolution Observatory (LEO) resulted in saturation excess overland flow and gully erosion in the convergent hillslope area. An array of 496 soil moisture sensors revealed a two-step saturation process. First, the downward movement of the wetting front brought soils to a relatively constant but still unsaturated moisture content. Second, soils were brought to saturated conditions from below in response to rising water tables. Convergent areas responded faster than upslope areas, due to contributions from lateral subsurface flow driven by the topography of the bottom boundary, which is comparable to impermeable bedrock in natural environments. This led to the formation of a groundwater ridge in the convergent area, triggering saturation excess runoff generation. This unique experiment demonstrates, at very high spatial and temporal resolution, the role of convergence on subsurface storage and flow dynamics. The results bring into question the representation of saturation excess overland flow in conceptual rainfall-runoff models and land-surface models, since flow is gravity-driven in many of these models and upper layers cannot become saturated from below. The results also provide a baseline to study the role of the co-evolution of ecological and hydrological processes in determining landscape water dynamics during future experiments in LEO.

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Salonvaara, Mikael, Philip Boudreaux, Andre Desjarlais, Florian Antretter, and Eric Werling. "Validation of Hygrothermal Simulations with Wall Performance Experiments in an Environmental Chamber." E3S Web of Conferences 172 (2020): 04010. http://dx.doi.org/10.1051/e3sconf/202017204010.

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Oak Ridge National Laboratory is developing a web tool, built on a rule-based expert system, that aids stakeholders in designing energy-efficient moisture-durable walls. Currently, the tool’s expert system database is mostly populated with expert opinion, but work is being done to incorporate durability assessment based on stochastic hygrothermal modeling. Chamber experiments have been conducted to validate the hygrothermal models. The measured temperature and humidity have been compared with those predicted by the hygrothermal model. Experiments and comparison to one-dimensional hygrothermal modeling results were completed with two walls, a Structural Insulated Panel (SIP) based wall and a Concrete Masonry Unit (CMU) based wall. The two walls were succumbed to typical Chicago weather in ORNL’s Heat, Air and Moisture chamber. The walls were sequentially exposed to different scenarios, including diffusion, wetting, air leakage and solar radiation. For the most part, the hygrothermal simulations can be successfully used to predict the performance of these wall systems for the moisture transport phenomenon. Errors between measured and simulated values decreased as measurements got closer to the interior side of the wall. The root mean square error was larger for relative humidity (up to 17.5%-RH for CMU) than for temperature (up to 4.5°C for CMU wall). The errors were larger for the CMU wall than the wood frame wall. The phenomenon, including liquid water, caused large discrepancies between measurement and simulation results, and simulated results showed slower drying of materials than measured results. The one-dimensional nature of the simulation model made simulating air leaks difficult but not impossible.

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A., Vivek Anand, Arumugam V., Jayalakshmi S., and Arvind Singh R. "Innovative approach for suppressing corrosion of SS304 steel in saline water environment." Anti-Corrosion Methods and Materials 65, no. 5 (September 3, 2018): 484–91. http://dx.doi.org/10.1108/acmm-01-2018-1889.

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Purpose The failure of structures and components made of SS304 steel because of corrosion in the presence of saline water environment is still an unsolved issue across the globe. Conventionally, coatings and inhibitors are used to mitigate corrosion. The purpose of this study is to propose a novel method to tackle corrosion by means of micro-patterning on the surface and to explore the relation between surface morphology, corrosion and wetting nature of micro-patterned SS304 Steel. Design/methodology/approach Groove-shaped micro-patterns were created on SS304 steel surface with varying ridge and channel widths. Wettability studies conducted on flat and micro-patterned steel surfaces using high speed camera. Corrosion tests carried out in saline water using an electrochemical test set-up to quantify the performance of micro-patterned surface over flat surface and scanning electron microscopic analysis to visualize the severity of corrosion on the surfaces of SS304 steel. Findings Wettability studies showed that the micro-patterned steel surfaces were hydrophobic. Corrosion rates of the micro-patterned steel surfaces were lower by more than an order of magnitude compared to that of the flat steel surface. Scanning electron microscopic analysis revealed that the micro-patterned steel surfaces had less surface damage compared to the flat surface. Originality/value The author shows that the remarkable corrosion resistance shown by the micro-patterned steel surfaces is attributed to their hydrophobicity, which reduced the contact between the surfaces and the corrosive liquid media. Results from the investigation indicate that micro-patterning of SS304 steel surfaces is an effective route to decrease corrosion.

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Bishop, Daniel A., A. Park Williams, Richard Seager, Arlene M. Fiore, Benjamin I. Cook, Justin S. Mankin, Deepti Singh, Jason E. Smerdon, and Mukund P. Rao. "Investigating the Causes of Increased Twentieth-Century Fall Precipitation over the Southeastern United States." Journal of Climate 32, no. 2 (December 28, 2018): 575–90. http://dx.doi.org/10.1175/jcli-d-18-0244.1.

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Abstract Much of the eastern United States experienced increased precipitation over the twentieth century. Characterizing these trends and their causes is critical for assessing future hydroclimate risks. Here, U.S. precipitation trends are analyzed for 1895–2016, revealing that fall precipitation in the southeastern region north of the Gulf of Mexico (SE-Gulf) increased by nearly 40%, primarily increasing after the mid-1900s. Because fall is the climatological dry season in the SE-Gulf and precipitation in other seasons changed insignificantly, the seasonal precipitation cycle diminished substantially. The increase in SE-Gulf fall precipitation was caused by increased southerly moisture transport from the Gulf of Mexico, which was almost entirely driven by stronger winds associated with enhanced anticyclonic circulation west of the North Atlantic subtropical high (NASH) and not by increases in specific humidity. Atmospheric models forced by observed SSTs and fully coupled models forced by historical anthropogenic forcing do not robustly simulate twentieth-century fall wetting in the SE-Gulf. SST-forced atmospheric models do simulate an intensified anticyclonic low-level circulation around the NASH, but the modeled intensification occurred farther west than observed. CMIP5 analyses suggest an increased likelihood of positive SE-Gulf fall precipitation trends given historical and future GHG forcing. Nevertheless, individual model simulations (both SST forced and fully coupled) only very rarely produce the observed magnitude of the SE-Gulf fall precipitation trend. Further research into model representation of the western ridge of the fall NASH is needed, which will help us to better predict whether twentieth-century increases in SE-Gulf fall precipitation will persist into the future.

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Zhang, Bin, Zhanbo Wei, Sean M. Schaeffer, Aizhen Liang, and Xueli Ding. "Recovery of bacterial communities and functions of soils under ridge tillage and no-tillage after different intensities and frequencies of drying-wetting disturbances in agroecosystems of northeastern China." CATENA 203 (August 2021): 105367. http://dx.doi.org/10.1016/j.catena.2021.105367.

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Peng, Gunnar G., Draga Pihler-Puzović, Anne Juel, Matthias Heil, and John R. Lister. "Displacement flows under elastic membranes. Part 2. Analysis of interfacial effects." Journal of Fluid Mechanics 784 (November 6, 2015): 512–47. http://dx.doi.org/10.1017/jfm.2015.589.

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We investigate the injection of inviscid gas into the narrow liquid-filled gap between a rigid base plate and an overlying elastic sheet. After an early-time transient in which the gas deflects the sheet into a large blister, the viscous liquid displaced by the expanding bubble starts to accumulate in a wedge which advances as the elastic sheet peels away from the base. We analyse theoretically the subsequent interaction between viscous forces, elastic (bending or tension) forces and capillary forces. Asymptotic expressions are derived for the speed of spreading of the bubble, which reveal that the effect of the capillary pressure drop at the bubble tip is to suck down the sheet over the liquid wedge and thereby reduce the speed. We show that the system passes through three different asymptotic regimes in sequence. At early times, capillary effects are weak and hence the spreading of the bubble is controlled dominantly by the viscous-peeling process at the wedge tip. The capillary forces grow in importance with time, and at late times they dominate viscous effects and balance with elastic forces, leading to quasi-static spreading. Finally, at very late times, the capillary suction generates a narrow bottleneck at the wedge tip, which pushes a large ridge of liquid ahead of it. These results hold in the framework of standard lubrication theory as well as with an improved lubrication model, which takes into account films of wetting liquid deposited behind the advancing bubble tip. The predictions of the model are shown to be in excellent agreement with the Navier–Stokes simulations and experimental results from Part 1 of this work.

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Mac Intyre, J. R., J. M. Gomba, Carlos Alberto Perazzo, P. G. Correa, and M. Sellier. "Thermocapillary migration of droplets under molecular and gravitational forces." Journal of Fluid Mechanics 847 (May 17, 2018): 1–27. http://dx.doi.org/10.1017/jfm.2018.306.

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We study the thermocapillary migration of two-dimensional droplets of partially wetting liquids on a non-uniformly heated surface. The effect of a non-zero contact angle is imposed through a disjoining–conjoining pressure term. The numerical results for two different molecular interactions are compared: on the one hand, London–van der Waals and ionic–electrostatics molecular interactions that account for polar liquids; on the other hand, long- and short-range molecular forces that model molecular interactions of non-polar fluids. In addition, the effect of gravity on the velocity of the drop is analysed. We find that for small contact angles, the long-time dynamics is independent of the molecular potential, and the footprint of the droplet increases with the square root of time. For intermediate contact angles we observe that polar droplets are more likely to break up into smaller volumes than non-polar ones. A linear stability analysis allows us to predict the number of droplets after breakup occurs. In this regime, the effect of gravity is stabilizing: it reduces the growth rates of the unstable modes and increases the shortest unstable wavelength. When breakup is not observed, the droplet moves steadily with a profile that consists in a capillary ridge followed by a film of constant thickness, for which we find power law dependencies with the cross-sectional area of the droplet, the contact angle and the temperature gradients. For large contact angles, non-polar liquids move faster than polar ones, and the velocity is proportional to the Marangoni stress. We find power law dependencies for the velocity for the different regimes of flow. The numerical results allow us to shed light on experimental facts such as the origin of the elongation of droplets and the existence of saturation velocity.

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van Gorcum, M., S. Karpitschka, B. Andreotti, and J. H. Snoeijer. "Spreading on viscoelastic solids: are contact angles selected by Neumann's law?" Soft Matter 16, no. 5 (2020): 1306–22. http://dx.doi.org/10.1039/c9sm01453e.

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Gremillard, Laurent, Eduardo Saiz, Velimir R. Radmilovic, and Antoni P. Tomsia. "Role of titanium on the reactive spreading of lead-free solders on alumina." Journal of Materials Research 21, no. 12 (December 2006): 3222–33. http://dx.doi.org/10.1557/jmr.2006.0393.

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The wetting of Sn3Ag-based alloys on Al2O3 has been studied using the sessile-drop configuration. Small additions of Ti decrease the contact angle of Sn3Ag alloys on alumina from 115° to 23°. Adsorption of Ti-species at the solid–liquid interface prior to reaction is the driving force for the observed decrease in contact angle, and the spreading kinetics is controlled by the kinetics of Ti dissolution into the molten alloy. The addition of Ti increases the transport rates at the solid–liquid interface, resulting in the formation of triple-line ridges that pin the liquid front and promote a wide variability in the final contact angles.

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ZHANG, Yong-Yong, Xi-Ning ZHAO, and Pu-Te WU. "Soil Wetting Patterns and Water Distribution as Affected by Irrigation for Uncropped Ridges and Furrows." Pedosphere 25, no. 3 (June 2015): 468–77. http://dx.doi.org/10.1016/s1002-0160(15)30014-x.

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Zuo, Biao, Houkuan Tian, Yongfeng Liang, Hao Xu, Wei Zhang, Li Zhang, and Xinping Wang. "Probing the rheological properties of supported thin polystyrene films by investigating the growth dynamics of wetting ridges." Soft Matter 12, no. 28 (2016): 6120–31. http://dx.doi.org/10.1039/c6sm00881j.

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Sarma, Pallav, and Khalid Aziz. "New Transfer Functions for Simulation of Naturally Fractured Reservoirs with Dual Porosity Models." SPE Journal 11, no. 03 (September 1, 2006): 328–40. http://dx.doi.org/10.2118/90231-pa.

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Summary This paper discusses new techniques for the modeling and simulation of naturally fractured reservoirs with dual-porosity models. Most of the existing dual-porosity models idealize matrix-fracture interaction by assuming orthogonal fracture systems (parallelepiped matrix blocks) and pseudo-steady state flow. More importantly, a direct generalization of single-phase flow equations is used to model multiphase flow, which can lead to significant inaccuracies in multiphase flow-behavior predictions. In this work, many of these existing limitations are removed in order to arrive at a transfer function more representative of real reservoirs. Firstly, combining the differential form of the single-phase transfer function with analytical solutions of the pressure-diffusion equation, an analytical form for a shape factor for transient pressure diffusion is derived to corroborate its time dependence. Further, a pseudosteady shape factor for rhombic fracture systems is also derived and its effect on matrix-fracture mass transfer demonstrated. Finally, a general numerical technique to calculate the shape factor for any arbitrary shape of the matrix block (i.e., nonorthogonal fractures) is proposed. This technique also accounts for both transient and pseudosteady-state pressure behavior. The results were verified against fine-grid single-porosity models and were found to be in excellent agreement. Secondly, it is shown that the current form of the transfer function used in reservoir simulators does not fully account for the main mechanisms governing multiphase flow. A complete definition of the differential form of the transfer function for two-phase flow is derived and combined with the governing equations for pressure and saturation diffusion to arrive at a modified form of the transfer function for two-phase flow. The new transfer function accurately takes into account pressure diffusion (fluid expansion) and saturation diffusion (imbibition), which are the two main mechanisms driving multiphase matrix-fracture mass transfer. New shape factors for saturation diffusion are defined. It is shown that the prediction of wetting-phase imbibition using the current form of the transfer function can be quite inaccurate, which might have significant consequences from the perspective of reservoir management. Fine-grid single-porosity models are used to verify the validity of the new transfer function. The results from single-block dual-porosity models and the corresponding single-porosity fine-grid models were in good agreement. Introduction A naturally fractured reservoir (NFR) can be defined as a reservoir that contains a connected network of fractures (planar discontinuities) created by natural processes such as diastrophism and volume shrinkage (Ordonez et al. 2001). Fractured petroleum reservoirs represent over 20% of the world's oil and gas reserves (Saidi 1983), but are, however, among the most complicated class of reservoirs. A typical example is the Circle Ridge fractured reservoir located on the Wind River Reservation in Wyoming, U.S.. This reservoir has been in production for more than 50 years but the total oil recovery until now has been less than 15% (www.fracturedreservoirs.com 2000). It is undeniable that reservoir characterization, modeling, and simulation of naturally fractured reservoirs present unique challenges that differentiate them from conventional, single-porosity reservoirs. Not only do the intrinsic characteristics of the fractures, as well as the matrix, have to be characterized, but the interaction between matrix blocks and surrounding fractures must also be modeled accurately. Further, most of the major NFRs have active aquifers associated with them, or would eventually be subjected to some kind of secondary recovery process such as waterflooding (German 2002), implying that it is essential to have a good understanding of the physics of multiphase flow for such reservoirs. This complexity of naturally fractured reservoirs necessitates the need for their accurate representation from a modeling and simulation perspective, such that production and recovery from such reservoirs be predicted and optimized.

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Okuda, Shu-hei, Shu-suke Yoshihara, Sungmin Kang, Masatoshi Tokita, and Junji Watanabe. "Formation of Regularly Spaced Wetting Ridges at 1 μm Intervals on the Surface of a Liquid-Crystalline Polymer." Langmuir 28, no. 41 (October 4, 2012): 14518–21. http://dx.doi.org/10.1021/la303335x.

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Song, Ying, and Min Zou. "Superhydrophobic surfaces by dynamic nanomasking and deep reactive ion etching." Proceedings of the Institution of Mechanical Engineers, Part N: Journal of Nanoengineering and Nanosystems 221, no. 2 (June 1, 2007): 41–48. http://dx.doi.org/10.1243/17403499jnn106.

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This paper reports a study on fabricating superhydrophobic surfaces with micro- and nanohierarchical topography by dynamic nanomasking (DNM) and deep reactive ion etching (DRIE). In this study, thin layers of gold (Au) were sputtered on silicon (Si) wafers followed by annealing the samples in a conventional furnace to break the thin films into Au nanoparticles attached to the Si surfaces. These randomly distributed nanoparticles served as dynamic nanomasks during DRIE processes, in which sulphur hexafluoride (SF6) and octofluorocyclobutane (C4F8) were used as etching and polymerization gases, respectively. Surface topography and wetting properties of the samples were characterized by scanning electron microscopy (SEM) and a video-based optical contact angle meter (VOCAM). SEM images show that this technique created micro-sized craters with Au nanoparticles residing on the ridges of the microstructures. The largest water contact angle (WCA) obtained by this method is about 163°. The surface superhydrophobicity is attributed to the combination of micro- and nano-hierarchical topography and surface polymerization.

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May, Jan-Hendrik, Stephen G. Wells, Timothy J. Cohen, Samuel K. Marx, Gerald C. Nanson, and Sophie E. Baker. "A soil Chronosequence on Lake Mega-Frome Beach Ridges and its Implications for Late Quaternary Pedogenesis and Paleoenvironmental Conditions in the Drylands of Southern Australia." Quaternary Research 83, no. 1 (January 2015): 150–65. http://dx.doi.org/10.1016/j.yqres.2014.11.002.

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AbstractThe terminal lake systems of central Australia are key sites for the reconstruction of late Quaternary paleoenvironments. Paleoshoreline deposits around these lakes reflect repeated lake filling episodes and such landforms have enabled the establishment of a luminescence-based chronology for filling events in previous studies. Here we present a detailed documentation of the morphology and chemistry of soils developed in four well-preserved beach ridges of late Pleistocene and mid-to-late Holocene age at Lake Callabonna to assess changes in dominant pedogenic processes. All soil profiles contain evidence for the incorporation of eolian-derived material, likely via the formation of desert pavements and vesicular horizons, and limited illuviation due to generally shallow wetting fronts. Even though soil properties in the four studied profiles also provide examples of parent material influence or site-specific processes related to the geomorphic setting, there is an overall trend of increasing enrichment of eolian-derived material since at least ~ 33 ka. Compared to the Holocene profiles, the derived average accumulation rates for the late Pleistocene profiles are significantly lower and may suggest that soils record important regional changes in paleoenvironments and dust dynamics related to shifts in the Southern Hemisphere westerlies.

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Palugan, Luca, Saliha Moutaharrik, Alessandra Maroni, Anastasia Anna Foppoli, Alice Melocchi, Carlo Vecchio, Andrea Gazzaniga, and Matteo Cerea. "Evaluation of Newly Designed and Traditional Punches in Manufacturing of Scored ODTs." Pharmaceutics 14, no. 10 (September 27, 2022): 2054. http://dx.doi.org/10.3390/pharmaceutics14102054.

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To overcome difficulties in splitting, uneven breaking and inconsistent dosing frequently reported with scored tablets, a novel punch was proposed for the manufacturing of easy breakable tablets (EBTs). In this work, the performance of the EBT punch was investigated vs. a ridged one for traditional breakable tablets (TBTs) using a furosemide powder formulation for orally disintegrating tablets (ODTs). A Face Centered Central Composite Design was applied to investigate the influence of punch type, compaction force, tablet weight and press rotation speed on the mechanical properties of ODTs, their behavior in aqueous fluids and aptitude for splitting. Mass uniformity and adequate crushing strength, friability, water uptake, disintegration and wetting times were obtained from both TBTs and EBTs. Interestingly, more favorable splitting behavior was shown by tablets manufactured by the novel punch, in view of lower mass loss and portion mass variability after breaking. The ease of breaking, accuracy of subdivision and mass loss of ODTs were also evaluated by a volunteer (n = 20) panel test. Less difficulty was found in splitting EBTs than TBTs (p < 0.05), and a larger number of tablets were properly broken into four parts. Thus, this study proved the usefulness of the EBT punch in overcoming drawbacks associated with divisible tablets.

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Halli, Hanamant M., Sanganabasappa Angadi, Prabhu Govindasamy, Raghavendra Madar, Manjanagouda S. Sannagoudar, Ahmed M. El-Sabrout, Abed Alataway, Ahmed Z. Dewidar, and Hosam O. Elansary. "Integrated Effect of Deficit Irrigation and Sowing Methods on Weed Dynamics and System Productivity of Maize–Cowpea Sequence on Vertisols." Agronomy 11, no. 4 (April 20, 2021): 808. http://dx.doi.org/10.3390/agronomy11040808.

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The aim of this study was to explore the effect of sowing methods and deficit irrigation on weed dynamics, yield and water-use efficiency (WUE) of the maize–cowpea system during the summer and monsoon seasons, respectively. The field experiment was carried out for two years (2015 and 2016) using a split design with three replicates under irrigated (maize) and rainfed (cowpea) conditions on vertisols of a semi-arid region. Treatments included three sowing methods [i.e., broad bed and furrow (BBF), corrugated furrow (CF) and ridges and furrow (RF)] and four irrigation levels [i.e., irrigation once in 10 days (I10D), irrigation at 40% (I40), at 50% (I50) and at 60% (I60) depletion]. The results indicated that, regardless of weed flora (monocots, dicots and sedges), the RF method produced higher weed density (2.09–2.98 No. m−2) compared to CF (2.00–2.80 No. m−2) and BBF (1.85–2.64 No. m−2) in maize at 30 and 60 days after sowing (DAS). The RF method with irrigation at I40 and I50 recorded significantly higher weed density, followed by the CF and BBF method. A similar trend was also observed with dry weight of weeds (monocot; 24.19%, dicot; 25.52%, and sedges; 29.80%) in maize at 30 and 60 DAS. Higher weed density and dry weight of weeds in the RF method with I40 was due to higher soil moisture availability and higher nutrient uptake due to larger lateral wetting of the soil and greater water use (29.27%). However, the BBF method favoured the growth of weeds (9.33–16.60%) in cowpea at 55 DAS and coped under rain-fed situation over CF and RF. The CF with moderate depletion (I50) method produced significantly higher maize equivalent yield (MEY) of cowpea (10,000 kg ha−1) with considerable reduction in the total water usage (19.33%). Therefore, under a water scarcity situation, growers can practice CF and I50 for higher yield and WUE of maize–cowpea sequence cropping.

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Wang, Lingxiao, Kai Yin, Qinwen Deng, Qiaoqiao Huang, Jun He, and Ji‐An Duan. "Wetting Ridge‐Guided Directional Water Self‐Transport." Advanced Science, October 17, 2022, 2204891. http://dx.doi.org/10.1002/advs.202204891.

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Cai, Zhuoyun, Artem Skabeev, Svetlana Morozova, and Jonathan T. Pham. "Fluid separation and network deformation in wetting of soft and swollen surfaces." Communications Materials 2, no. 1 (February 24, 2021). http://dx.doi.org/10.1038/s43246-021-00125-2.

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AbstractWhen a water drop is placed onto a soft polymer network, a wetting ridge develops at the drop periphery. The height of this wetting ridge is typically governed by the drop surface tension balanced by elastic restoring forces of the polymer network. However, the situation is more complex when the network is swollen with fluid, because the fluid may separate from the network at the contact line. Here we study the fluid separation and network deformation at the contact line of a soft polydimethylsiloxane (PDMS) network, swollen with silicone oil. By controlling both the degrees of crosslinking and swelling, we find that more fluid separates from the network with increasing swelling. Above a certain swelling, network deformation decreases while fluid separation increases, demonstrating synergy between network deformation and fluid separation. When the PDMS network is swollen with a fluid having a negative spreading parameter, such as hexadecane, no fluid separation is observed. A simple balance of interfacial, elastic, and mixing energies can describe this fluid separation behavior. Our results reveal that a swelling fluid, commonly found in soft networks, plays a critical role in a wetting ridge.

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Chaudhuri, Krishnaroop, and Jonathan T. Pham. "Temperature-dependent soft wetting on amorphous, uncrosslinked polymer surfaces." Soft Matter, 2022. http://dx.doi.org/10.1039/d2sm00301e.

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Chaudhuri, Krishnaroop, and Jonathan T. Pham. "Temperature-dependent soft wetting on amorphous, uncrosslinked polymer surfaces." Soft Matter, 2022. http://dx.doi.org/10.1039/d2sm00301e.

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Mokbel, Dominic, Sebastian Aland, and Stefan Karpitschka. "Stick-slip contact line motion on Kelvin-Voigt model substrates." Europhysics Letters, May 4, 2022. http://dx.doi.org/10.1209/0295-5075/ac6ca6.

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Abstract The capillary traction of a liquid contact line causes highly localized deformations in soft solids, tremendously slowing down wetting and dewetting dynamics by viscoelastic braking. Enforcing nonetheless large velocities leads to the so-called stick-slip instability, during which the contact line periodically depins from its own wetting ridge. The mechanism of this periodic motion and, especially, the role of the dynamics in the ﬂuid have remained elusive, partly because a theoretical description of the unsteady soft wetting problem is not available so far. Here we present the ﬁrst numerical simulations of the full unsteady soft wetting problem, with a full coupling between the liquid and the solid dynamics. We observe three regimes of soft wetting dynamics: steady viscoelastic braking at slow speeds, stick-slip motion at intermediate speeds, followed by a region of viscoelastic braking where stick-slip is suppressed by liquid damping, which ultimately gives way to classical wetting dynamics, dominated by liquid dissipation.

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Cousins, Joseph R. L., Brian R. Duffy, Stephen K. Wilson, and Nigel J. Mottram. "Young and Young–Laplace equations for a static ridge of nematic liquid crystal, and transitions between equilibrium states." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 478, no. 2259 (March 2022). http://dx.doi.org/10.1098/rspa.2021.0849.

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Motivated by the need for greater understanding of systems that involve interfaces between a nematic liquid crystal, a solid substrate and a passive gas that include nematic–substrate–gas three-phase contact lines, we analyse a two-dimensional static ridge of nematic resting on a solid substrate in an atmosphere of passive gas. Specifically, we obtain the first complete theoretical description for this system, including nematic Young and Young–Laplace equations, and then, making the assumption that anchoring breaking occurs in regions adjacent to the contact lines, we use the nematic Young equations to determine the continuous and discontinuous transitions that occur between the equilibrium states of complete wetting, partial wetting and complete dewetting. In particular, in addition to continuous transitions analogous to those that occur in the classical case of an isotropic liquid, we find a variety of discontinuous transitions, as well as contact-angle hysteresis, and regions of parameter space in which there exist multiple partial wetting states that do not occur in the classical case.

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Zhang, Jianqiang, Xuejiao Wang, Zhaoyue Wang, Shangfa Pan, Bo Yi, Liqing Ai, Jun Gao, Frieder Mugele, and Xi Yao. "Wetting ridge assisted programmed magnetic actuation of droplets on ferrofluid-infused surface." Nature Communications 12, no. 1 (December 2021). http://dx.doi.org/10.1038/s41467-021-27503-1.

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AbstractFlexible actuation of droplets is crucial for biomedical and industrial applications. Hence, various approaches using optical, electrical, and magnetic forces have been exploited to actuate droplets. For broad applicability, an ideal approach should be programmable and be able to actuate droplets of arbitrary size and composition. Here we present an “additive-free” magnetic actuation method to programmably manipulate droplets of water, organic, and biological fluids of arbitrary composition, as well as solid samples, on a ferrofluid-infused porous surface. We specifically exploit the spontaneously formed ferrofluid wetting ridges to actuate droplets using spatially varying magnetic fields. We demonstrate programmed processing and analysis of biological samples in individual drops as well as the collective actuation of large ensembles of micrometer-sized droplets. Such model respiratory droplets can be accumulated for improved quantitative and sensitive bioanalysis - an otherwise prohibitively difficult task that may be useful in tracking coronavirus.

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Onishi, Junya, Gaukhar K. Paluashova, Yulia I. Shirokova, and Haruyuki Fujimaki. "Salt Removal by Combining a Permanent Skip Furrow Irrigation and Salt Removal Sheet." Frontiers in Agronomy 3 (April 13, 2021). http://dx.doi.org/10.3389/fagro.2021.659722.

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Skip furrow irrigation (SFI) can save water by irrigating every alternate furrow. Usually, irrigated furrows are alternated at each irrigation event under SFI. If irrigated furrows are fixed (permanent SFI, PSFI), more water may be saved by reducing the wetting area, and salts may accumulate on the dry side of the ridge. Salt removal sheet, a method of collecting salts on the sheet laid on the soil surface utilizing high evaporation demand in drylands, may be an efficient measure for removal of accumulated salt under PSFI. We evaluated salinity movement and water saving under PSFI through a field experiment in Uzbekistan. In addition, a salt removal sheet was applied to the shoulder of the ridge on the drier side under PSFI to evaluate its potential in removing salt from the soil with the practice. The results showed that salts tend to accumulate on the dry side of the ridge, and the amount of irrigation water was halved without a large crop yield reduction. The PSFI + Sheet was able to catch 6.4% of salts in the top 10 cm soil layer.

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Hardt, Steffen, and Glen McHale. "Flow and Drop Transport Along Liquid-Infused Surfaces." Annual Review of Fluid Mechanics 54, no. 1 (September 21, 2021). http://dx.doi.org/10.1146/annurev-fluid-030121-113156.

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Liquid-infused surfaces (LISs) are composite solid–liquid surfaces with remarkable features such as liquid repellency, self-healing, and the suppression of fouling. This review focuses on the fluid mechanics on LISs, that is, the interaction of surfaces with a flow field and the behavior of drops on such surfaces. LISs can be characterized by an effective slip length that is closely related to their drag reduction property, which makes them suitable for several applications, especially for turbulent flows. Drag reduction, however, is compromised by failure mechanisms such as the drainage of lubricant from surface textures. The flow field can also sculpt the lubricant layer in a coupled self-organization process. For drops, the lubricant reduces drop pinning and increases drop mobility, but also results in a wetting ridge and the associated concept of an apparent contact angle. Design of LIS wettability and topography can induce low-friction drop motion, and drops can dynamically shape the lubricant ridges and film thickness. Expected final online publication date for the Annual Review of Fluid Mechanics, Volume 54 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Gandee, Hunter, Yimin Zhou, John Lee, Juan Chomali, Haobo Xu, and Solomon Adera. "Unique ice dendrite morphology on state-of-the-art oil-impregnated surfaces." Proceedings of the National Academy of Sciences 120, no. 1 (December 27, 2022). http://dx.doi.org/10.1073/pnas.2214143120.

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Due to its multifaceted impact in various applications, icing and ice dendrite growth has been the focus of numerous studies in the past. Dendrites on wetting (hydrophilic) and nonwetting (hydrophobic) surfaces are sharp, pointy, branching, and hairy. Here, we show a unique dendrite morphology on state-of-the-art micro/nanostructured oil-impregnated surfaces, which are commonly referred to as slippery liquid-infused porous surfaces or liquid-infused surfaces. Unlike the dendrites on traditional textured hydrophilic and hydrophobic surfaces, the dendrites on oil-impregnated surfaces are thick and lumpy without pattern. Our experiments show that the unique ice dendrite morphology on lubricant-infused surfaces is due to oil wicking into the porous dendritic network because of the capillary pressure imbalance between the surface texture and the dendrites. We characterized the shape complexity of the ice dendrites using fractal analysis. Experiments show that ice dendrites on textured oil-impregnated surfaces have lower fractal dimensions than those on traditional lotus leaf-inspired air-filled porous structures. Furthermore, we developed a regime map that can be used as a design guideline for micro/nanostructured oil-impregnated surfaces by capturing the complex effects of oil chemistry, oil viscosity, and wetting ridge volume on dendrite growth and morphology. The insights gained from this work inform strategies to reduce lubricant depletion, a major bottleneck for the transition of micro/nanostructured oil-impregnated surfaces from bench-top laboratory prototypes to industrial use. This work will assist the development of next-generation depletion-resistant lubricant-infused ice-repellent surfaces.

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Lee, Dong-Ki, Su Young Choi, Min Soo Park, and Young Hak Cho. "Wetting properties of hybrid structure with hydrophilic ridges and hydrophobic channels." Applied Physics A 124, no. 2 (January 30, 2018). http://dx.doi.org/10.1007/s00339-018-1595-4.

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Mora, Peter, Gabriele Morra, Dave A. Yuen, and Ruben Juanes. "Influence of Wetting on Viscous Fingering Via 2D Lattice Boltzmann Simulations." Transport in Porous Media, June 3, 2021. http://dx.doi.org/10.1007/s11242-021-01629-8.

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AbstractWe present simulations of two-phase flow using the Rothman and Keller colour gradient Lattice Boltzmann method to study viscous fingering when a “red fluid” invades a porous model initially filled with a “blue” fluid with different viscosity. We conducted eleven suites of 81 numerical experiments totalling 891 simulations, where each suite had a different random realization of the porous model and spanned viscosity ratios in the range $$M\in [0.01,100]$$ M ∈ [ 0.01 , 100 ] and wetting angles in the range $$\theta _w\in [180^\circ ,0^\circ ]$$ θ w ∈ [ 180 ∘ , 0 ∘ ] to allow us to study the effect of these parameters on the fluid-displacement morphology and saturation at breakthrough (sweep). Although sweep often increased with wettability, this was not always so and the sweep phase space landscape, defined as the difference in saturation at a given wetting angle relative to saturation for the non-wetting case, had hills, ridges and valleys. At low viscosity ratios, flow at breakthrough is localized through narrow fingers that span the model. After breakthrough, the flow field continues to evolve and the saturation continues to increase albeit at a reduced rate, and eventually exceeds 90% for both non-wetting and wetting cases. The existence of a complicated sweep phase space at breakthrough, and continued post-breakthrough evolution suggests the hydrodynamics and sweep is a complicated function of wetting angle, viscosity ratio and time, which has major potential implications to Enhanced Oil Recovery by water flooding, and hence, on estimates of global oil reserves. Validation of these results via experiments is required to ensure they translate to field studies.

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Journal articles on the topic 'Wetting ridge'

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