Efficient Computational Model for Non-Axisymmetric Flow and Heat Transfer in Rotating Cavity

2008 ◽  
Author(s):  
L. He
Keyword(s):  
Large Scale ◽  
Axisymmetric Flow ◽  
Small Scale ◽  
Vortex Pairs ◽  
Spectral Technique ◽  
Flow And Heat Transfer ◽  
Large Length ◽  
Computational Resources ◽  
Fourier Harmonics ◽  
Computational Predictions

Existence of large scale unsteady flow structures manifested in contra-rotating vortex pairs has been previously identified in rotor disc cavities. The non-axisymmetric nature with a unknown number of vortices presents a computational challenge as a full 360° circumferential domain will be needed, requiring significant computational resources. A novel circumferential spatial Fourier spectral technique is adopted in the present work to facilitate efficient computational predictions of the non-axisymmetric flows. Given that the flow non-uniformities in the circumferential direction are of large length scales, only a few circumferential Fourier harmonics would be needed, resulting in a drastic reduction in number of circumferential mesh points to be required. The modeling formulations and implementation aspects will be described. Computational examples will be presented to demonstrate the validity and effectiveness of the present modeling approach. The computational results show that the non-axisymmetric flow patterns in terms of the number of vortex pairs are sensitive to small scale external disturbances. It is also indicated that the occurrence of a non-axisymmetric flow might be captured by the present Fourier solution with even one harmonic.

Efficient Computational Model for Nonaxisymmetric Flow and Heat Transfer in Rotating Cavity

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
L. He
Keyword(s):  
Large Scale ◽  
Small Scale ◽  
Vortex Pairs ◽  
Spectral Technique ◽  
Flow And Heat Transfer ◽  
Large Length ◽  
Rotor Disk ◽  
Computational Resources ◽  
Fourier Harmonics ◽  
Computational Predictions

Existence of large scale unsteady flow structures manifested in contrarotating vortex pairs has been previously identified in rotor disk cavities. The nonaxisymmetric nature with an unknown number of vortices presents a computational challenge, as a full 360 deg circumferential domain will be needed, requiring significant computational resources. A novel circumferential spatial Fourier spectral technique is adopted in the present work to facilitate efficient computational predictions of the nonaxisymmetric flows. Given that the flow nonuniformities in the circumferential direction are of large length scales, only a few circumferential Fourier harmonics would be needed, resulting in a drastic reduction in number of circumferential mesh points to be required. The modeling formulations and implementation aspects will be described. Computational examples will be presented to demonstrate the validity and effectiveness of the present modeling approach. The computational results show that the nonaxisymmetric flow patterns, in terms of the number of vortex pairs, are sensitive to small scale external disturbances. It is also indicated that the occurrence of a nonaxisymmetric flow might be captured by the present Fourier solution with even one harmonic.

scholarly journals Experiments on transitions of baroclinic waves in a differentially heated rotating annulus

2005 ◽  
Vol 12 (6) ◽  
pp. 1033-1041 ◽  
Author(s):  
Th. von Larcher ◽  
C. Egbers
Keyword(s):  
Large Scale ◽  
Axisymmetric Flow ◽  
Vertical Axis ◽  
Surface Flow ◽  
Working Fluid ◽  
Small Scale ◽  
Complex Flows ◽  
Wave Regime ◽  
Baroclinic Waves ◽  
Dependent Behaviour

Abstract. Experiments of baroclinic waves in a rotating, baroclinic annulus of fluid are presented for two gap widths. The apparatus is a differentially heated cylindrical gap, rotated around its vertical axis of symmetry, cooled from within, with a free surface, and filled with de-ionised water as working fluid. The surface flow was observed with visualisation technique while thermographic measurements gave a detailed understanding of the temperature distribution and its time-dependent behaviour. We focus in particular on transitions between different flow regimes. Using a wide gap, the first transition from axisymmetric flow to the regular wave regime was characterised by complex flows. The transition to irregular flows was smooth, where a coexistence of the large-scale jet-stream and small-scale vortices was observed. Furthermore, temperature measurements showed a repetitive separation of cold vortices from the inner wall. Experiments using a narrow gap showed no complex flows but strong hysteresis in the steady wave regime, with up to five different azimuthal wave modes as potential steady and stable solutions.

DYNAMIC SIMILARITY IN GROUNDWATER FLOW WITH A FREE SURFACE

1963 ◽  
Vol 41 (1) ◽  
pp. 90-94
Author(s):  
A. E. Scheidegger
Keyword(s):  
Free Surface ◽  
Groundwater Flow ◽  
Large Scale ◽  
Small Error ◽  
Small Scale ◽  
Drainage Ditches ◽  
Scaling Relationships ◽  
Large Length ◽  
River Valleys ◽  
Laboratory Models

The scaling relationships applicable for the construction of laboratory models representing groundwater flow with a free surface are deduced. It is found that, for large length reductions, these scaling relationships are very difficult to satisfy. The scaling relationships, however, can generally be used for transferring results from small-scale systems (such as drainage ditches) to large-scale systems (such as river valleys). However, if one is willing to allow a small error by assuming that the boundary conditions may be correctly scaled if the pressure at the free surface in the prototype and in the model is taken as zero, much simpler scaling relationships can be obtained, which can be easily satisfied in practice.

scholarly journals The DOE Systems Biology Knowledgebase (KBase)

2016 ◽  
Author(s):  
Adam P Arkin ◽  
Rick L Stevens ◽  
Robert W Cottingham ◽  
Sergei Maslov ◽  
Christopher S Henry ◽  
...  
Keyword(s):  
Systems Biology ◽  
Open Source Software ◽  
Large Scale ◽  
Community Dynamics ◽  
Department Of Energy ◽  
Small Scale ◽  
Grand Challenge ◽  
Web Browser ◽  
Data Platform ◽  
Computational Resources

AbstractThe U.S. Department of Energy Systems Biology Knowledgebase (KBase) is an open-source software and data platform designed to meet the grand challenge of systems biology — predicting and designing biological function from the biomolecular (small scale) to the ecological (large scale). KBase is available for anyone to use, and enables researchers to collaboratively generate, test, compare, and share hypotheses about biological functions; perform large-scale analyses on scalable computing infrastructure; and combine experimental evidence and conclusions that lead to accurate models of plant and microbial physiology and community dynamics. The KBase platform has (1) extensible analytical capabilities that currently include genome assembly, annotation, ontology assignment, comparative genomics, transcriptomics, and metabolic modeling; (2) a web-browser-based user interface that supports building, sharing, and publishing reproducible and well-annotated analyses with integrated data; (3) access to extensive computational resources; and (4) a software development kit allowing the community to add functionality to the system.

scholarly journals Opportunities from low-resolution modelling of river morphology in remote parts of the world

2014 ◽  
Vol 2 (1) ◽  
pp. 9-19 ◽  
Author(s):  
M. Nones ◽  
M. Guerrero ◽  
P. Ronco
Keyword(s):  
Cross Sections ◽  
Large Scale ◽  
Initial Conditions ◽  
Large Rivers ◽  
Small Scale ◽  
First Case ◽  
The World ◽  
High Level ◽  
Computational Resources

Abstract. River morphodynamics are the result of a variety of processes, ranging from the typical small-scale of fluid mechanics (e.g. flow turbulence dissipation) to the large-scale of landscape evolution (e.g. fan deposition). However, problems inherent in the long-term modelling of large rivers derive from limited computational resources and the high level of process detail (i.e. spatial and temporal resolution). These modelling results depend on processes parameterization and calibrations based on detailed field data (e.g. initial morphology). Thus, for these cases, simplified tools are attractive. In this paper, a simplified 1-D approach is presented that is suited for modelling very large rivers. A synthetic description of the variations of cross-sections shapes is implemented on the basis of satellite images, typically also available for remote parts of the world. The model's flexibility is highlighted here by presenting two applications. In the first case, the model is used for analysing the long-term evolution of the lower Zambezi River (Africa) as it relates to the construction of two reservoirs for hydropower exploitation. In the second case, the same model is applied to study the evolution of the middle and lower Paraná River (Argentina), particularly in the context of climate variability. In both cases, having only basic data for boundary and initial conditions, the 1-D model provides results that are in agreement with past studies and therefore shows potential to be used to assist sediment management at the watershed scale or at boundaries of more detailed models.

Small-Scale Science to Large-Scale Profession

2000 ◽  
Vol 45 (4) ◽  
pp. 396-398
Author(s):  
Roger Smith
Keyword(s):  
Large Scale ◽  
Small Scale

Development of Physics Learning Module Based on Guided Inquiry with Light Wave Material in Class XI of Senior High School

2020 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Evi Rahmawati ◽  
Irnin Agustina Dwi Astuti ◽  
N Nurhayati
Keyword(s):  
Large Scale ◽  
Learning Strategy ◽  
Student Response ◽  
Average Score ◽  
Small Scale ◽  
Design Development ◽  
Teacher Response ◽  
Student Responses ◽  
Analysis Design ◽  
Scientific Skills

IPA Integrated is a place for students to study themselves and the surrounding environment applied in daily life. Integrated IPA Learning provides a direct experience to students through the use and development of scientific skills and attitudes. The importance of integrated IPA requires to pack learning well, integrated IPA integration with the preparation of modules combined with learning strategy can maximize the learning process in school. In SMP 209 Jakarta, the value of the integrated IPA is obtained from 34 students there are 10 students completed and 24 students are not complete because they get the value below the KKM of 68. This research is a development study with the development model of ADDIE (Analysis, Design, Development, Implementation, and Evaluation). The use of KPS-based integrated IPA modules (Science Process sSkills) on the theme of rainbow phenomenon obtained by media expert validation results with an average score of 84.38%, average material expert 82.18%, average linguist 75.37%. So the average of all aspects obtained by 80.55% is worth using and tested to students. The results of the teacher response obtained 88.69% value with excellent criteria. Student responses on a small scale acquired an average score of 85.19% with highly agreed criteria and on the large-scale student response gained a yield of 86.44% with very agreed criteria. So the module can be concluded receiving a good response by the teacher and students.

Planetary gentrification and urban (re)development

2019 ◽  
Vol 61 (1) ◽  
pp. 5-13 ◽  
Author(s):  
Loretta Lees
Keyword(s):  
Low Income ◽  
Policy Making ◽  
Large Scale ◽  
Urban Redevelopment ◽  
Urban Transformation ◽  
Small Scale ◽  
Income Groups ◽  
Low Income Groups

Abstract Gentrification is no-longer, if it ever was, a small scale process of urban transformation. Gentrification globally is more often practised as large scale urban redevelopment. It is state-led or state-induced. The results are clear – the displacement and disenfranchisement of low income groups in favour of wealthier in-movers. So, why has gentrification come to dominate policy making worldwide and what can be done about it?

AGRICULTURAL PRODUCTION OF CA DONG PEOPLE IN RESETTLEMENT AREA OF TRANH RIVER HYDROPOWER NUMBER 2: CURRENT SITUATION AND IMPACT FACTORS

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Bùi Thị Bích Lan
Keyword(s):  
Social Relations ◽  
Agricultural Production ◽  
Large Scale ◽  
Transition Process ◽  
Impact Factors ◽  
Small Scale ◽  
Scale Production ◽  
Technical Application ◽  
Production Models ◽  
Role Of The State

In Vietnam, the construction of hydropower projects has contributed significantly in the cause of industrialization and modernization of the country. The place where hydropower projects are built is mostly inhabited by ethnic minorities - communities that rely primarily on land, a very important source of livelihood security. In the context of the lack of common productive land in resettlement areas, the orientation for agricultural production is to promote indigenous knowledge combined with increasing scientific and technical application; shifting from small-scale production practices to large-scale commodity production. However, the research results of this article show that many obstacles in the transition process are being posed such as limitations on natural resources, traditional production thinking or the suitability and effectiveness of scientific - technical application models. When agricultural production does not ensure food security, a number of implications for people’s lives are increasingly evident, such as poverty, preserving cultural identity, social relations and resource protection. Since then, it has set the role of the State in researching and building appropriate agricultural production models to exploit local strengths and ensure sustainability.

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