Three-dimensional convection in a two-layer system with anomalous thermocapillary effect

2002 ◽  
Vol 14 (11) ◽  
pp. 3899-3911 ◽  
Author(s):  
Thomas Boeck ◽  
Alexander Nepomnyashchy ◽  
Ilya Simanovskii ◽  
Alexander Golovin ◽  
Leonid Braverman ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Thermocapillary Effect ◽  
Layer System

scholarly journals Experimental Study on Coherent Structures by Particles Suspended in Half-Zone Thermocapillary Liquid Bridges: Review

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 105
Author(s):  
Ichiro Ueno
Keyword(s):  
Coherent Structures ◽  
Three Dimensional ◽  
Wave Number ◽  
Flow Structures ◽  
Liquid Bridges ◽  
Thermocapillary Effect ◽  
Particle Accumulation ◽  
Azimuthal Wave Number ◽  
Experimental Approaches ◽  
Particle Behaviour

Coherent structures by the particles suspended in the half-zone thermocapillary liquid bridges via experimental approaches are introduced. General knowledge on the particle accumulation structures (PAS) is described, and then the spatial–temporal behaviours of the particles forming the PAS are illustrated with the results of the two- and three-dimensional particle tracking. Variations of the coherent structures as functions of the intensity of the thermocapillary effect and the particle size are introduced by focusing on the PAS of the azimuthal wave number m=3. Correlation between the particle behaviour and the ordered flow structures known as the Kolmogorov–Arnold—Moser tori is discussed. Recent works on the PAS of m=1 are briefly introduced.

Nonlinear development of oscillatory instability in a three-layer system under the joint action of buoyancy and thermocapillary effect

2011 ◽  
Vol 23 (1) ◽  
pp. 012103 ◽  
Author(s):  
Ilya B. Simanovskii ◽  
Antonio Viviani ◽  
Frank Dubois ◽  
Jean-Claude Legros
Keyword(s):  
Joint Action ◽  
Oscillatory Instability ◽  
Thermocapillary Effect ◽  
Layer System ◽  
Nonlinear Development

scholarly journals Effect of heater size on heat transfer in a falling liquid film

2021 ◽  
pp. 50-55
Author(s):  
В.В. Кузнецов
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Analytical Formula ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Physical Factors ◽  
Thermocapillary Effect ◽  
Average Value ◽  
Surface Deformations ◽  
Falling Liquid Film

Проведены расчеты полей скорости и температуры, а также положение границы раздела жидкость-газ при стекании тонкой пленки жидкости по плоской подложке, наклоненной к горизонту. На подложке расположен нагреватель квадратной формы, мощность которого фиксирована, а размеры варьировались в ходе расчетов:- одним из перспективных методов отвода высоких тепловых потоков от электронного оборудования являются технологии, использующие тонкие пленки жидкости, движущиеся по охлаждаемой поверхности. Целью работы было исследование зависимости динамики и теплообмена в пленки от размера нагревателя;- на основе разработанной трехмерной нестационарной модели движения проведены расчеты теплообмена в движущейся поенке. При этом учитывалось действие всех основных физческих факторов при их взаимодействии: диффузионный и конвективный теплопереносы, зависимость вязкости от температуры, термокапиллярный эффект, появление и эволюция поверхностных деформаций;- установлено, что размер нагревателя существенно влияет на поля температуры и поверхностные деформации, а также на значение температурных экстремумов. Выведена аналитическая формула для расчета наибольшего достигаемого на подложке превышения температуры её среднего значения;- результаты могут применяться при проектировании систем охлаждения электронного оборудования. On the basis of the developed three-dimensional non-stationary model of motion, calculations of heat transfer in a moving roll were carried out. In this case, the action of all the main physical factors during their interaction was taken into account: diffusion and convective heat transfer, the dependence of viscosity on temperature, the thermocapillary effect, the appearance and evolution of surface deformations.  it was found that the size of the heater significantly affects the temperature fields and surface deformations, as well as the value of temperature extremes. An analytical formula is derived for calculating the maximum temperature rise attainable on the substrate of its average value.

scholarly journals Three-dimensional transient flow to a partially penetrated well with variable discharge in a general three-layer aquifer system

2020 ◽  
Author(s):  
Qinggao Feng ◽  
Xiaola Feng ◽  
Hongbin Zhan
Keyword(s):  
Boundary Conditions ◽  
Transient Flow ◽  
Three Dimensional ◽  
Late Time ◽  
Layer System ◽  
Middle Point ◽  
Bottom Boundary ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Constant Head

Abstract. A general analytical model for three-dimensional flow in a three-layered aquifer system with a partial penetration well having a variable discharge of pumping is developed by taking account of the interface flow on the adjacent layers. This general three-layer system includes the conventional aquitard-aquifer-aquitard system as a subset and does not require that the permeability contrasts of different layers must be greater than a few orders of magnitude, and does not ignore any flow components (either vertical or horizontal) in any particular layer. The pumping well of infinitesimal radius is screened at any portion of the middle layer. Three widely used top and bottom boundary conditions are considered that can be specified as a constant-head boundary (Case1) or a no-flux boundary (Case 2), and a constant-head boundary at the top in combination with a no-flux boundary at the bottom (Case 3). Laplace domain solutions for dimensionless drawdown are obtained by the use of Hankel transformation, and associated time-domain solutions are evaluated numerically. The newly obtained solutions include some available solutions for two- or single-layer aquifer systems as subsets. The drawdowns for individual layers caused by a well with an exponentially decreased discharge are explored as an example of illustration. The results indicate that the pumped layer drawdown close to the partially penetrated well is mainly influenced by the variable pumping rate. The late-time drawdowns for all layers are remarkably affected by the chosen types of top and bottom boundary conditions, and the drawdown for Case 3 is greater than that for Case 1 and smaller than that for Case 2. Additionally, the effect of the pumped layer anisotropy on drawdowns in the three-layer system is significant, and the anisotropy of the unpumped layers significantly affects the drawdown in the whole aquifer system without large contrast of hydraulic conductivity between the unpumped layers and the pumped layer. The drawdowns in all three layers are greatly affected by the location and length of well screen, and a larger drawdown can be seen at the position that is closer to the middle point of the screen of the partially penetrating pumping well.

Oceanic warm cloud layers within multilevel cloud systems observed by satellite measurements

2020 ◽  
Author(s):  
Qi Liu ◽  
Yuhao Ding ◽  
Ping Lao
Keyword(s):  
Double Layer ◽  
Radiative Forcing ◽  
Lower Layer ◽  
Numerical Models ◽  
Three Dimensional ◽  
Single Layer ◽  
Layer System ◽  
Cloud Systems ◽  
Warm Cloud ◽  
Double Layer System

<p>Low-level warm clouds are a major component in multilayered cloud systems and are generally hidden from the top-down view of satellites with passive measurements. By using spaceborne radar data with fine vertical resolution, this study conducts an investigation on oceanic warm clouds embedded in multilayered structures. The occurrences of warm cloud overlapping and the geometric features of several kinds of warm cloud layers are examined. It is found that there are three main types of cloud systems that involve warm cloud layers, including warm single layer clouds, cold-warm double layer clouds and warm-warm double layer clouds. The two types of double layer clouds account for 23% and in the double layer occurrences warm-warm double layer subsets contribute about 13%. The global distribution patterns of these three types differ from each other. Single-layer warm clouds and the lower warm clouds in the cold-warm double layer system have nearly identical geometric parameters, while the upper and lower layer warm clouds in the warm-warm double layer system are distinct from the previous two forms of warm cloud layers. In contrast to the independence of the two cloud layers in cold-warm double layer system, the two kinds of warm cloud layers in the warm-warm double layer system may be coupled. The distance between the two layers in the warm-warm double layer system is weakly dependent on cloud thickness. Given the upper and lower cloud layer with moderate thickness around 1 km, the cloudless gap reaches its maximum exceeding 600 m. As the two cloud layers become even thinner or thicker, the cloudless gap decreases in thickness. It is believed that such knowledge on cloud overlapping is critical for fully understanding the distribution of warm clouds in three-dimensional space. The results derived in this study could help validating cloud results of numerical models, which are indeed three-dimensional in nature. They could also be used to improve the estimation of cloud radiative forcing, since it is affected by cloud occurrences and especially their vertical structures. It should be pointed out that solid explanations for the above cloud features cannot be presented by only using these satellite data themselves. </p>

scholarly journals Co-Culturing of Endothelial and Cancer Cells in a Nanofibrous Scaffold-Based Two-Layer System

2020 ◽  
Vol 21 (11) ◽  
pp. 4128
Author(s):  
Ye-Seul Oh ◽  
Min-Ho Choi ◽  
Jung-In Shin ◽  
Perry Ayn Mayson A. Maza ◽  
Jong-Young Kwak
Keyword(s):  
Cancer Cells ◽  
Culture System ◽  
Lower Layer ◽  
Three Dimensional ◽  
Nanofibrous Scaffold ◽  
Vascular Endothelial ◽  
Layer System ◽  
Chemical Hypoxia ◽  
Steady Growth ◽  
Endothelial Growth Factor

Angiogenesis is critical for local tumor growth. This study aimed to develop a three-dimensional two-layer co-culture system to investigate effects of cancer cells on the growth of endothelial cells (ECs). Poly(ε-caprolactone) (PCL) nanofibrous membranes were generated via electrospinning of PCL in chloroform (C-PCL-M) and chloroform and dimethylformamide (C/DMF-PCL-M). We assembled a two-layer co-culture system using C-PCL-M and C/DMF-PCL-M for EC growth in the upper layer with co-cultured cancer cells in the lower layer. In the absence of vascular endothelial growth factor (VEGF), growth of bEND.3 ECs decreased on C/DMF-PCL-M but not on C-PCL-M with time. Growth of bEND.3 cells on C/DMF-PCL-M was enhanced through co-culturing of CT26 cancer cells and enhanced growth of bEND.3 cells was abrogated with anti-VEGF antibodies and sorafenib. However, EA.hy926 ECs displayed steady growth and proliferation on C/DMF-PCL-M, and their growth was not further increased through co-culturing of cancer cells. Moreover, chemical hypoxia in CT26 cancer cells upon treatment with CoCl2 enhanced the growth of co-cultured bEND.3 cells in the two-layer system. Thus, EC growth on the nanofibrous scaffold is dependent on the types of ECs and composition of nanofibers and this co-culture system can be used to analyze EC growth induced by cancer cells.

scholarly journals Bacterial Infection-Mimicking Three-Dimensional Phagocytosis and Chemotaxis in Electrospun Poly(ε-caprolactone) Nanofibrous Membrane

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 569
Author(s):  
Seung-Jun Lee ◽  
Perry Ayn Mayson A Maza ◽  
Gyu-Min Sun ◽  
Petr Slama ◽  
In-Jeong Lee ◽  
...  
Keyword(s):  
Culture System ◽  
Three Dimensional ◽  
3D Culture ◽  
Culture Conditions ◽  
Lung Epithelial Cells ◽  
Nanofibrous Membrane ◽  
Infection Model ◽  
Layer System

In this study, we developed a three-dimensional (3D) in vitro infection model to investigate the crosstalk between phagocytes and microbes in inflammation using a nanofibrous membrane (NM). Poly(ε-caprolactone) (PCL)-NMs (PCL-NMs) were generated via electrospinning of PCL in chloroform. Staphylococcus aureus and phagocytes were able to adhere to the nanofibers and phagocytes engulfed S. aureus in the PCL-NM. The migration of phagocytes to S. aureus was evaluated in a two-layer co-culture system using PCL-NM. Neutrophils, macrophages and dendritic cells (DCs) cultured in the upper PCL-NM layer migrated to the lower PCL-NM layer containing bacteria. DCs migrated to neutrophils that cultured with bacteria and then engulfed neutrophils in two-layer system. In addition, phagocytes in the upper PCL-NM layer migrated to bacteria-infected MLE-12 lung epithelial cells in the lower PCL-NM layer. S. aureus-infected MLE-12 cells stimulated the secretion of tumor necrosis factor-α and IL-1α in 3D culture conditions, but not in 2D culture conditions. Therefore, the PCL-NM-based 3D culture system with phagocytes and bacteria mimics the inflammatory response to microbes in vivo and is applicable to the biomimetic study of various microbe infections.

scholarly journals Dynamics of spiral waves and bubble formation in a closed chemical system of thin photosensitive excitable media

2021 ◽  
Vol 2145 (1) ◽  
pp. 012025
Author(s):  
Kritsana Khaothong ◽  
Vikanda Chanchang ◽  
Jarin Kanchanawarin ◽  
Malee Sutthiopad ◽  
Chaiya Luengviriya
Keyword(s):  
Thin Layer ◽  
Bubble Formation ◽  
Three Dimensional ◽  
Spiral Waves ◽  
Excitable Media ◽  
Chemical System ◽  
Layer System ◽  
Cardiac Tissues ◽  
Bz Reaction ◽  
Life Threatening

Abstract Spiral waves have been observed in a thin layer of excitable media. Especially, electrical spiral waves in cardiac tissues connect to cardiac tachycardia and life-threatening fibrillations. The Belousov-Zhabotinsky (BZ) reaction is the most widely used system to study the dynamics of spiral waves in experiments. When the light sensitive Ru(bpy)3 2+ is used as the catalyst, the BZ reaction becomes photosensitive and the excitability of the reaction can be controlled by varying the illumination intensity. However, the typical photosensitive BZ reaction produces many CO2 bubbles so the spiral waves are always studied in thin layer media with opened top surfaces to release the bubbles. In this work, we develop new chemical recipes of the photosensitive BZ reaction which produces less bubbles. To observe the production of bubbles, we investigate the dynamics of spiral waves in a closed thin layer system. The results show that both the speed of spiral waves and the number of bubbles increase with the concentration of sulfuric acid (H2SO4) and sodium bromate (NaBrO3). For high initial concentrations of both reactants, the size of bubbles increases with time until the wave structures are destroyed. We expect that the chemical recipes reported here can be used to study complicated dynamics of three-dimensional spiral waves in thick BZ media where the bubbles cannot escape.

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