Test of Cross-Section Shape of Air-Liquid Interface in Microgrooves With Micro-PIV Method

2011 ◽  
Author(s):  
Xuelei Nie ◽  
Xuegong Hu ◽  
Tao Wang ◽  
Dawei Tang
Keyword(s):  
Heat Transfer ◽  
Cross Section ◽  
Great Influence ◽  
Liquid Interface ◽  
Polynomial Curves ◽  
Micro Piv ◽  
Cross Section Shape ◽  
Section Shape ◽  
The Cross ◽  
Air Liquid Interface

Evaporation of liquid meniscus formed in microgrooves is associated with very high heat transfer rates, but the cross-section shape of air-liquid interface has a great influence to the heat transfer in microgrooves. But the real cross-section shape of interface in microgrooves is still unknown for us. In this work, the micro-PIV (Particle Image Velocimetry) method is used to test the cross-section shape of air-liquid interface in microgrooves. In the experiment, the camera is focus on different planes from top of the microgrooves to the bottom of the microgrooves. In each plane, we can see the boundary between the air and liquid through small particles added into the liquid. The positions of boundary in each plane for a given cross section are drawn in two-dimension coordinate. Then the cross-section shape of interface in microgrooves can be seen from the fitting curve. The results show that the cross-section shapes of the interface in microgrooves are not round, but polynomial curves. The curvature of interface in microgrooves changes along a single curve. Besides, the polynomial curves also vary along axial direction of the microgrooves. The variations are more obvious in vertical microgrooves than in horizontal microgrooves.

scholarly journals Designing for People’s Safety on Flooded Streets: Uncertainties and the Influence of the Cross-Section Shape, Roughness and Slopes on Hazard Criteria

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2119
Author(s):  
Luís Mesquita David ◽  
Rita Fernandes de Carvalho
Keyword(s):  
Cross Section ◽  
Overland Flow ◽  
Rectangular Cross Section ◽  
Safety Hazard ◽  
Cross Section Shape ◽  
Section Shape ◽  
Flood Flows ◽  
The Cross ◽  
Flooding Risk

Designing for exceedance events consists in designing a continuous route for overland flow to deal with flows exceeding the sewer system’s capacity and to mitigate flooding risk. A review is carried out here on flood safety/hazard criteria, which generally establish thresholds for the water depth and flood velocity, or a relationship between them. The effects of the cross-section shape, roughness and slope of streets in meeting the criteria are evaluated based on equations, graphical results and one case study. An expedited method for the verification of safety criteria based solely on flow is presented, saving efforts in detailing models and increasing confidence in the results from simplified models. The method is valid for 0.1 m2/s 0.5 m2/s. The results showed that a street with a 1.8% slope, 75 m1/3s−1 and a rectangular cross-section complies with the threshold 0.3 m2/s for twice the flow of a street with the same width but with a conventional cross-section shape. The flow will be four times greater for a 15% street slope. The results also highlighted that the flood flows can vary significantly along the streets depending on the sewers’ roughness and the flow transfers between the major and minor systems, such that the effort detailing a street’s cross-section must be balanced with all of the other sources of uncertainty.

Finite-size analysis and the influence of the cross-section shape of the granular column collapses

2021 ◽  
Author(s):  
Teng Man ◽  
Herbert Huppert ◽  
Ling Li ◽  
Sergio Galindo-Torres
Keyword(s):  
Size Effect ◽  
Cross Section ◽  
Finite Size ◽  
Size Analysis ◽  
Cross Section Shape ◽  
Section Shape ◽  
The Cross ◽  
Shape Influence ◽  
Deposition Morphology ◽  
Granular Column

<p>The collapse of granular columns, which sheds light on the kinematics, dynamics, and deposition morphology of mass-driven flows, is crucial for understanding complex flows in both natural and engineering systems, such as debris flows and landslides. However, our research shows that a strong size effect and cross-section shape influence exist in this test. Thus, it is essential to better understand these effects. In this study, we explore the influence of both relative column sizes and cross-section shapes on the run-out behavior of collapsed granular columns and analyze their influence on the deposition morphology with the discrete element method (DEM) with Voronoi-based spheropolyhedron particles. We link the size effect that occurs in granular column collapse problems to the finite-size scaling functions and investigate the characteristic correlation length associated with the granular column collapses. The collapsing behavior of granular columns with different cross-section shapes is also studied, and we find that particles tend to accumulate in the direction normal to the edge of the cross-section instead of the vertex of it. The differences in the run-out behavior in different directions when the cross-section is no longer a circle can also be explained by the finite-size analysis we have performed in this study. We believe that such a study is crucial for us to better understand how granular material flows, how it deposits, and how to consider the size effect in the rheology of granular flows.</p>

Parametric study of the cross-section shape of aluminium tubes in dynamic three-point bending

2019 ◽  
Vol 136 ◽  
pp. 315-322 ◽  
Author(s):  
David Bilston ◽  
Dong Ruan ◽  
Artur Candido ◽  
Yvonne Durandet
Keyword(s):  
Cross Section ◽  
Parametric Study ◽  
Three Point Bending ◽  
Cross Section Shape ◽  
Section Shape ◽  
The Cross

scholarly journals Influence of the cross section shape on the behaviour of SRG-confined prismatic concrete specimens

2015 ◽  
Vol 49 (3) ◽  
pp. 869-887 ◽  
Author(s):  
Georgia E. Thermou ◽  
Konstantinos Katakalos ◽  
George Manos
Keyword(s):  
Cross Section ◽  
Cross Section Shape ◽  
Section Shape ◽  
The Cross

A note on the elastic contact stiffness of a layered medium

1993 ◽  
Vol 8 (12) ◽  
pp. 3229-3232 ◽  
Author(s):  
Huajian Gao ◽  
Tsai-Wei Wu
Keyword(s):  
Perturbation Method ◽  
Cross Section ◽  
Layered Medium ◽  
Contact Stiffness ◽  
Elastic Contact ◽  
Cross Section Shape ◽  
Section Shape ◽  
Cylindrical Punch ◽  
The Cross

A perturbation method is used to confirm that the elastic contact stiffness associated with a flat-ended punch indenting a layered medium is insensitive to the cross-section shape of the punch as long as the shape does not differ too much from a circle. This result supports the practice of modeling nonaxisymmetric indenters such as Vickers or Berkovich indenters as an axisymmetric flat-ended cylindrical punch.

Numerical Simulation of Acoustic Resonance in Closed Side Branch With Different Cross-Section Shapes

2018 ◽  
Author(s):  
Jiang LiuYi ◽  
Zhang Hong ◽  
Duan QingQuan
Keyword(s):  
Cross Section ◽  
Research Work ◽  
Branch Pipe ◽  
Acoustic Resonance ◽  
Side Branch ◽  
Pipeline System ◽  
Detached Eddy Simulation ◽  
Cross Section Shape ◽  
Section Shape ◽  
The Cross

There are many closed side branches in the gas conveying pipeline system. When the gas passes through the closed side branch, the shear layer will arouse the acoustic resonance in the closed side branch, which is harmful to the safe operation of the pipeline. The research work is insufficient about the influence of the cross-section shape of the closed side branch on acoustic resonance. Using the Detached-Eddy Simulation (DES) model, the acoustic resonance characteristics caused by the side branch pipe with different square cross-sections are simulated at the inlet boundary conditions of 25 m/s, 30 m/s and 35 m/s. The results show that in the center axis of the side branch, a 1/4 wavelength standing wave was formed, and the acoustic resonance occurs at a higher Strouhal number in circular branch. The cross-section shape of the side branch does not affect the acoustic resonance frequency, but it has a certain influence on the amplitude of pressure fluctuation and has a significant influence on the high-order frequency components.

scholarly journals Leaf and inflorescence axis anatomy of Brazilian species of Rapateoideae (Rapateaceae, Poales)

2015 ◽  
Vol 87 (1) ◽  
pp. 157-171 ◽  
Author(s):  
Ângela L. Daltin ◽  
Aline Oriani ◽  
Vera L. Scatena
Keyword(s):  
Cross Section ◽  
Leaf Blade ◽  
Diagnostic Value ◽  
Fiber Bundles ◽  
Vascular Bundles ◽  
Abaxial Epidermis ◽  
Cross Section Shape ◽  
Inflorescence Axis ◽  
Section Shape ◽  
The Cross

The anatomy of leaves and inflorescence axes of Spathanthus (2 spp.), Rapatea (2 spp.), Cephalostemon(1 sp.), and Duckea(1 sp.) (Rapateoideae, Rapateaceae) was studied to identify useful characters for taxonomy. The cross-section shape of inflorescence axis differentiates the genera, while the cross-section shape and structure of leaf midrib has a specific value. The following characteristics are exclusive of Spathanthus: silica cells randomly distributed in the leaf epidermis; plicate chlorenchyma in the leaf blade; presence of fiber bundles in the mesophyll and in the inflorescence axis parenchyma. Spathanthus is also distinguished by the number, type and distribution of vascular bundles in the inflorescence axis. The genus Rapatea is characterized by the presence of stomata and silica cells only on the abaxial epidermis of the leaves and chlorenchyma composed of arm cells in the leaf blade. Characteristics with diagnostic value for Cephalostemon riedelianusare: leaf epidermal cells with straight to slightly sinuous walls in frontal view, inflorescence axes presenting a defined cortex, fiber bundles facing the larger vascular bundles and a fistulous pith. The anatomical characteristics of the leaves and inflorescence axes thus proved to be of taxonomic value in generic and specific levels. They are also useful to differentiate Rapateoideae from other subfamilies of Rapateaceae.

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