Theoretical and experimental studies of the boundaries between two immiscible liquids in a vortex flow with a free surface

2016 ◽  
Vol 71 (4) ◽  
pp. 447-453
Author(s):  
T. O. Chaplina ◽  
A. V. Kistovich ◽  
E. V. Stepanova
Keyword(s):  
Free Surface ◽  
Vortex Flow ◽  
Experimental Studies ◽  
Immiscible Liquids

Spiral structure of the liquid particles trajectories near free surface of the vortex

2019 ◽  
pp. 67-77
Author(s):  
Анатолий Васильевич Кистович ◽  
Татьяна Олеговна Чаплина ◽  
Евгения Вячеславовна Степанова
Keyword(s):  
Free Surface ◽  
Velocity Field ◽  
Vortex Flow ◽  
Experimental Studies ◽  
Logarithmic Spiral ◽  
Zero Approximation ◽  
Helical Line ◽  
Liquid Particle ◽  
Particles Trajectories ◽  
Compound Vortex

Экспериментально и аналитически исследованы характеристики вихревого течения со свободной поверхностью, образующегося в результате вращения активаторного диска, расположенного на дне цилиндрического контейнера, заполненного водой. Получены аналитические выражения, показывающие, что траектории жидких частиц вблизи поверхности вихря представляют собой трехмерные спирали, по которым происходит течение от периферии к центу вихря. Показано, что рассчитанные и визуализированные траектории жидких частиц хорошо согласуются между собой и относятся к классу пространственных логарифмических спиралей. The work is aimed to compare results of analytical and experimental modeling of vortex fluid flow. The compound flow of liquid (water) occurs in a vertical cylindrical container without upper endwall under the action of the disk rotating at the bottom endwall. The two main components of the emerging flow are the toroidal vortex and the vortex with vertical axis. The equations are written in the cylindrical coordinate system dictated by the geometry of the problem. On the basis of the existing analytical expression, which describes the free surface form of the compound vortex in the zero approximation, an approach is developed to describe the trajectories of individual “liquid particles”. The obtained result allows to explore the velocity field structure near the free surface. The obtained expressions indicate that the velocity field near free surface becomes more pronounced in the tangent direction. This result is confirmed in the experimental studies of the compound vortex flow. The analytical forms of liquid particle trajectories near and on the free surface of the compound vortex are obtained. The general particle movement is from the container sidewall along the free surface to its center and further down the spiral-helical line. The images of the visualized particles trajectories both on the free surface (logarithmic spiral) and in the liquid depth are obtained in experiments and testify in favor of the implemented approach to the construction of analytical solution of the liquid particle motion for the vortex flow of the mentioned type. The correspondence of the calculated free surface forms obtained with the help of analytical expressions and those observed in the experiments with different parameters of the vortex flow shows that the developed approach to the problem can be based on a simplified description.

MELTING ABOUT A HEATED CYLINDER IN AN ICE-FILLED SQUARE ENCLOSURE WITH AN ISOTHERMALS FREE SURFACE

1999 ◽  
Vol 23 (3-4) ◽  
pp. 409-423
Author(s):  
P.H. Oosthuizen ◽  
J.T. Paul
Keyword(s):  
Free Surface ◽  
Numerical Study ◽  
Experimental Studies ◽  
Freezing Temperature ◽  
Lower Surface ◽  
Uniform Temperature ◽  
Square Enclosure ◽  
Heated Cylinder ◽  
Finite Element Procedure ◽  
Side Walls

A numerical study of the flow about and heat transfer from a heated cylinder centrally positioned in a square enclosure containing ice has been undertaken. The cylinder is heated to a uniform temperature that is higher than the freezing temperature of water and melting, therefore, occurs in the vicinity of the cylinder. The two side-walls of the enclosure are kept at a uniform temperature that is below the freezing temperature. The conditions considered here are such that there can be significant natural convection in the water near the cylinder. The lower surface of the enclosure is assumed to be adiabatic. The liquid has a free surface which is assumed to be flat. In most previous numerical studies of such a situation it has been assumed that the free surface is adiabatic. In experimental studies of the is type of flow, however, the free surface is often effectively cooled. In order to evaluate the effect of this, it has here been assumed that the free surface is at the uniform temperature that is below the freezing temperature but that is, in general, higher than that of the cooled side-walls. The governing equations have been expressed in dimensionless form and solved using a finite element procedure. The effect of the various governing parameters on the mean cylinder Nusselt number and on the thickness of the melted region about the cylinder have mainly been considered. The effect of the assumed free-surface temperature has, in particular, been studied.

Experimental Studies of Hydrodynamic Interaction of Two Bodies in Waves

2015 ◽  
Author(s):  
Quan Zhou ◽  
Ming Liu ◽  
Heather Peng ◽  
Wei Qiu
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Potential Flow ◽  
Numerical Solutions ◽  
Experimental Studies ◽  
Low Frequency ◽  
Surface Elevation ◽  
Linear Potential ◽  
Free Surface Elevation ◽  
Two Bodies

There are challenges in the prediction of low-frequency load and especially the resonant free surface elevation between two bodies in close proximity. Most of the linear potential-flow based seakeeping programs currently used by the industry over-predict the free surface elevation between the vessels/bodies and hence the low-frequency loadings on the hulls. Various methods, such as the lid technique, have been developed to suppress the unrealistic values of low-frequency forces by introducing artificial damping coefficients. However, without the experimental data, it is challenging to specify the coefficients. This paper presents the experimental studies of motions of two bodies with various gaps and the wave elevations between bodies. Model tests were performed at the towing tank of Memorial University. The objective was to provide benchmark data for further numerical studies of the viscous effect on the free surface predictions. The experimental data were compared with numerical solutions based on potential flow methods. The effect of tank walls were examined. Preliminary uncertainty analysis was also carried out.

scholarly journals SIZING AND EXPERIMENTAL STUDY OF A SOLAR STILL FOR THE PRODUCTIVITY OF WATER DESALINATION IN SOUTH-WEST OF ALGERIA – BECHAR: التصميم والدراسة التجريبية لجهاز التقطير الشمسي لإنتاجية تحلية المياه في جنوب غرب الجزائر – بشار

2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Abdelkarim Maamar Abdelkader, Bounegta Bachir Mohammed
Keyword(s):  
Drinking Water ◽  
Free Surface ◽  
Surface Area ◽  
Evaporation Rate ◽  
Salt Content ◽  
Experimental Studies ◽  
Water Desalination ◽  
Solar Still ◽  
Free Surface Area ◽  
The Third World

Algeria, like many countries belonging mostly to the Third World, has considerable water resources saline (salt content ranging between 1500 and 2000 ppm, exceeding the required standards for drinking water and therefore unfit for consumption). We must therefore think of making use these huge reserves interested in desalination techniques. The stain majored is therefore to achieve a distiller solar plan which meets these needs in drinking water. The absorber surface of the modified solar still is coated with black enamel paint and covered with copper chips. The evaporation rate of the water in the solar still is directly proportional to the exposure area of the water. Thus the productivity of the solar still increases with the free surface area of the water in the basin. The distillate yield was found to have improved considerably, especially when the water depth was high. The study also indicated some design features that would further enhance the improvement in output due to the modification made, the evaporation rate is proportional to the temperature of the free surface area of the water only. A general model based on heat transfer balances in each component of the system was developed to predict the mass of freshwater. The efficiency of this still was about 65% and can produce about 5.13 l/m2 per day, experimental studies and the outcomes are discussed in the article. We propose a new design of the cascading solar desalination still with obstacles and preheating of inlet water.

An Analysis of the Vortex Flow in the Cyclone Separator

1962 ◽  
Vol 84 (4) ◽  
pp. 609-616 ◽  
Author(s):  
J. L. Smith
Keyword(s):  
Free Surface ◽  
Vortex Flow ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Cyclone Separator ◽  
Rotating Fluids ◽  
Axial Distribution ◽  
Integral Analysis ◽  
Weir Flow ◽  
Momentum Integral

The theory of rotating fluids is applied to the flow in the cyclone. The effects of radial instabilities in the boundary layers on the walls are discussed. The dynamics of the central core in the flow are studied in a simple nonviscous model which exhibits wave propagation and weir flow similar to a free surface flow. A momentum-integral analysis is used to show the effect of friction and to predict the axial distribution of radial inflow.

Modeling of Size Effects in Diffusion Driven Processes at Nanoscale - Large Atomic and Mesoscale Methods

2017 ◽  
Vol 12 ◽  
pp. 38-73
Author(s):  
Tomasz Wejrzanowski ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Free Surface ◽  
Size Effects ◽  
Experimental Studies ◽  
High Energy ◽  
Intergranular Phase ◽  
Wide Range ◽  
Microstructure Effect

The results of the studies presented here are devoted to understanding of microstructure effect on the processes and properties driven by diffusion. The role of various interfaces (intergranular, phase, free surface), as the high-energy defects, is underlined and investigated with special attention. The methodology relevant to analyses of the microstructural processes is first briefly presented. The capability and limitations of classical molecular dynamics, mesoscale Monte Carlo and cellular automaton techniques are described. Two examples of the diffusion driven processes analyzed at various length and time scale are shown: namely, grain growth in nanometallic materials and melting of thin embedded films. The modeling results are also accompanied with experimental studies. Thanks to application of numerical methods, models of relevant processes were proposed, which enabled to provide quantitative relationships between microstructure and the process kinetics. Such relationships can be later used for design of optimized materials for wide range of applications.

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