scholarly journals Mechanisms of formation vortex structures at the liquid-gas interface with an adsorption layer

2020 ◽  
pp. 31-38
Author(s):  
A.I. Shmyrova ◽  
◽  
A. V. Shmyrov ◽  
Keyword(s):  
Stream Flow ◽  
Dimensionless Parameter ◽  
Flow Instability ◽  
Solid Sphere ◽  
Potential Mechanism ◽  
System Behavior ◽  
Flat Interface ◽  
3D Geometry ◽  
Mechanisms Of Formation ◽  
Elasticity Number

Experimental results of a homogeneous (along the coordinate transverse to the stream) flow instability during the interaction with a film of surfactant adsorbed at the flat interface are presented. The flow was formed at a point-like heat by radiation and a source of surfactants (acetone drops). It is proved that a small value of the film shear viscosity is one of the requirements for the vortices formation process. The possibility to use the dimensionless parameter (the elasticity number) to describe the system behavior in 3D geometry is shown. A potential mechanism for the vortices origin is proposed. The results of the visualization of the water surface uniform flow around a solid sphere are presented.

Suppression of Boiling Flow Oscillations in Parallel Microchannels by Inlet Restrictors

2005 ◽  
Vol 128 (3) ◽  
pp. 251-260 ◽  
Author(s):  
Ali Koşar ◽  
Chih-Jung Kuo ◽  
Yoav Peles
Keyword(s):  
Dimensionless Parameter ◽  
Flow Instability ◽  
Flow Boiling ◽  
Heat Fluxes ◽  
Mass Fluxes ◽  
Boiling Flow ◽  
Flow Oscillations ◽  
Parallel Channels ◽  
Geometrical Effects ◽  
Parallel Microchannels

Geometrical effects of MEMS-based microfabricated inlet orifices on the suppression of parallel channel and upstream compressible volume instabilities commonly exhibited during flow boiling in parallel microchannels have been investigated. The heat fluxes at the onset of unstable boiling have been obtained over effective heat fluxes ranging from 9 to 614W∕cm2 and mass fluxes from 115to389kg∕m2s. A dimensionless parameter M, which accounts for the pressure drop increase imposed by the inlet restrictors, has been used to correlate the extent of flow instability suppression. It has been shown that the onset of unstable boiling asymptotically increases with M. At sufficiently high M values, parallel channels and upstream compressible volume instabilities are completely eradicated although it gives way to another instability to develop, namely, the critical heat flux conditions. A correlation has been developed in terms of M to predict the conditions leading to unstable boiling.

scholarly journals Turbulence: mechanics and structure of anomalous scaling

2001 ◽  
Vol 8 (4/5) ◽  
pp. 197-200 ◽  
Author(s):  
S. N. Gordienko ◽  
S. S. Moiseev
Keyword(s):  
Turbulent Flows ◽  
Dimensionless Parameter ◽  
Broad Class ◽  
Power Laws ◽  
Turbulent Fluctuation ◽  
Governing Parameter ◽  
Mechanisms Of Formation ◽  
Characteristic Scales ◽  
Insight Into

Abstract. As the finite correlation time of a force driving turbulence is taken into account, a new, dimensionless parameter occurs in the theory of turbulence. This new parameter is responsible for two different mechanisms of formation of anomalous spectra. The first mechanism is related to the change of a governing parameter, which defines the spectrum of turbulent fluctuation. The second mechanism is associated with spontaneous formation of characteristic scales that differ parametrically from the scale of the external force. The last mechanism can explain the intermittent structure of turbulent flows. The appropriate discrete set of the possible characteristic scales and anomalous spectra has been calculated. The results give a new insight into the concept of universality: there is a set of universal power laws, although occurrence in the spectrum segments described by one or another power law from this set depends on the dimensionless parameter mentioned above. It is noted that for the broad class of geophysical flows, the new dimensionless parameter is connected with the so-called degree of turbulence, which guarantees that the smallness of this parameter, as the degree of turbulence is usually small enough. That explains the important role of the Kolmogorov spectrum in geophysical applications.

Emotional Impact Feedback Changes How We Remember Negative Autobiographical Experiences

2010 ◽  
Vol 57 (5) ◽  
pp. 354-359 ◽  
Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange
Keyword(s):  
Well Being ◽  
The Other ◽  
Personal Perspective ◽  
Emotional Impact ◽  
Potential Mechanism ◽  
Negative Experiences ◽  
Negative Memory ◽  
The Relationship ◽  
Negative Memories ◽  
Over Time

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.

Use of Magnetic Resonance Imaging (MRI) to Determine the 3D Geometry in the Human Rectum

Endoscopy ◽  
2004 ◽  
Vol 36 (10) ◽  
Author(s):  
BP McMahon ◽  
JB Frøkjær ◽  
A Bergmann ◽  
DH Liao ◽  
E Steffensen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
3D Geometry ◽  
Human Rectum ◽  
Magnetic Resonance Imaging Mri

The innovative space as the most important element of theregional socio-economic space

2019 ◽  
pp. 60-70
Author(s):  
Larysa Gromozdova ◽  
Inna Stenicheva
Keyword(s):  
Basic Element ◽  
Information Support ◽  
Space Region ◽  
Regional Innovation ◽  
Economic Space ◽  
Mechanisms Of Formation ◽  
Innovation Space ◽  
Space Mechanisms ◽  
Constituent Elements

Purpose of the article: to determine the essence of different elements ofsocio-economic space of the region. Construction of the structure and isolationof individual elements of socio-economic space as a multi-vector formation.This article highlights the essence and different approaches to defining theconcepts, structure and mechanisms of formation of economic and social spacesof the region, innovation space as a basic element of socio-economic space.Research Methods: The methodological basis of the research is the fundamentalprinciples of economic theory, regional economy, scientific views and approachesof foreign and domestic scientists. To achieve the purpose of the study, themethods used at the empirical and theoretical levels were used: axiomatic,abstract, system-structural analysis, analogies and comparisons, graphoanalytic,by which the characterization of the nature of the concepts of space, socioeconomic space, as well as innovation space region. Their general properties,structure and functions are described.The criteria of optimality and balancesof interests in the formation of different types of space in the region areconsidered. The classification of the regional space is proposed, and the networkconnections of the innovation space according to components and elements arerevealed, which allows to study deeply the social, economic and other problemsof development of the region.Scientific novelty: the classification of regionalspace by separate constituent elements is proposed. The concept of “innovationspace” was introduced into scientific circulation, the scheme of networkconnections of the innovation space with other elements of the regional socioeconomic space was developed. Conclusions and Prospects for Further Research:In today’s context, it is possible to significantly improve the economic stateof development of Ukrainian regions by using a scientifically sound andcomprehensive approach to defining and studying the concepts of socioeconomic and innovative space.In the further study it is necessary to considerin detail the mechanism of organizational activity of innovation space in theregion. It is very important to pay attention to information support for theformation of the innovation space, the creation of a regional legal field ofinnovation space, mechanisms for coordinating regional innovation activitieswithin the innovation space, as well as the influence of internal and externalfactors on the formation and development of the innovation space.

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