A validation of a 3D CFD model for predicting local subcooling of the moderator in the vicinity of calandria tubes in a CANDU-6 reactor is performed. The small scale moderator experiments performed at Sheridan Park Ex...
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ISBN:
(纸本)9784888982566
A validation of a 3D CFD model for predicting local subcooling of the moderator in the vicinity of calandria tubes in a CANDU-6 reactor is performed. The small scale moderator experiments performed at Sheridan Park Experimental Laboratory(SPEL) in Ontario, Canada[1] is used for the validation. Also a comparison is made between previous CFD analyses based on 2DMOTH and PHOENICS, and the current analysis for the same SPEL experiment. For the current model, a set of grid structures for the same geometry as the experimental test section is generated and the momentum, heat and continuity equations are solved by CFX-4.3, a CFD code developed by AEA technology. The matrix of calandria tubes is simplified by the porous media approach. The standard k-Ε turbulence model associated with logarithmic wall treatment and SIMPLEC algorithm on the body fitted grid are used. Buoyancy effects are accounted for by the Boussinesq approximation. For the test conditions simulated in this study, the flow pattern identified is the buoyancy-dominated flow, which is generated by the interaction between the dominant buoyancy force by heating and inertial momentum forces by the inlet jets. As a result, the current CFD moderator analysis model predicts the moderator temperature reasonably, and the maximum error against the experimental data is kept at less than 2.0°C over the whole domain. The simulated velocity field matches with the visualization of SPEL experiments quite well.
Internet connectivity is defined by a set of routing protocols which let the routers that comprise the Internet backbone choose the best route for a packet to reach its destination. One way to improve the security and...
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Internet connectivity is defined by a set of routing protocols which let the routers that comprise the Internet backbone choose the best route for a packet to reach its destination. One way to improve the security and performance of Internet is to routinely examine the routing data. In this case study, we show how interactive visualization of Border Gateway Protocol (BGP) data helps characterize routing behavior, identify weaknesses in connectivity which could potentially cripple the Internet, as well as detect and explain actual anomalous events.
data mining is the process of extracting implicit, valuable, and interesting information from large sets of data. visualization is the process of visually exploring data for pattern and trend analysis, and it is a com...
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data mining is the process of extracting implicit, valuable, and interesting information from large sets of data. visualization is the process of visually exploring data for pattern and trend analysis, and it is a common method of browsing spatial datasets to look for patterns. However the growing volume of spatial datasets make it difficult for humans to browse such datasets in their entirety, and data mining algorithms are needed to filter out large uninteresting parts of spatial datasets. We construct a web-based visualization software package for observing the summarization of spatial patterns and temporal trends. We also present data mining algorithms for filtering out vast parts of datasets for spatial outlier patterns. The algorithms were implemented and tested with a real-world set of Minneapolis-St. Paul (Twin Cities) traffic data.
The analysis of multidimensional functions is important in many engineering disciplines, and poses a major problem as the number of dimensions increases. Previous visualization approaches focus on representing three o...
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The analysis of multidimensional functions is important in many engineering disciplines, and poses a major problem as the number of dimensions increases. Previous visualization approaches focus on representing three or fewer dimensions at a time. This paper presents a new focus+context visualization that provides an integrated overview of an entire multidimensional function space, with uniform treatment of all dimensions. The overview is displayed with respect to a user-controlled polar focal point in the function's parameter space. Function value patterns are viewed along rays that emanate from the focal point in all directions in the parameter space, and represented radially around the focal point in the visualization. data near the focal point receives proportionally more screen space than distant data. This approach scales smoothly from two dimensions to 10-20, with a 1000 pixel range on each dimension.
The current state of the art in visualization research places strong emphasis on different techniques to derive insight from disparate types of data. However, little work has investigated the visualization process its...
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The current state of the art in visualization research places strong emphasis on different techniques to derive insight from disparate types of data. However, little work has investigated the visualization process itself. The information content of the visualization process - the results, history, and relationships between those results - is addressed by this work. A characterization of the visualization process is discussed, leading to a general model of the visualization exploration process. The model, based upon a new parameter derivation calculus, can be used for automated reporting, analysis, or visualized directly. An XML-based language for expressing visualization sessions using the model is also described. These sessions can then be shared and reused by collaborators. The model, along with the XML representation, provides an effective means to utilize information within the visualization process to further data exploration.
Visualizing second-order 3D tensor fields continue to be a challenging task. Although there are several algorithms that have been presented, no single algorithm by itself is sufficient for the analysis because of the ...
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Visualizing second-order 3D tensor fields continue to be a challenging task. Although there are several algorithms that have been presented, no single algorithm by itself is sufficient for the analysis because of the complex nature of tensor fields. In this paper, we present two new methods, based on volume deformation, to show the effects of the tensor field upon its underlying media. We focus on providing a continuous representation of the nature of the tensor fields. Each of these visualization algorithms is good at displaying some particular properties of the tensor field.
Useful techniques for information visualization allow engineers or analysts to produce works of art. A work entitled "Financial Reminiscences" is an example of such works. This work has been produced using a...
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Useful techniques for information visualization allow engineers or analysts to produce works of art. A work entitled "Financial Reminiscences" is an example of such works. This work has been produced using a visualization technique for financial analysis. This technique is not only a tool for generating images. It is closely related to the information visualized in the work. Thus, the audience needs to understand the visualization technique and then to analyze the information.
The purpose of this work is to build a computerized system for the delineation of upper airway structures via MRI and to evaluate its effectiveness for routine clinical use in aiding diagnosis of upper airway disorder...
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ISBN:
(纸本)0819444286
The purpose of this work is to build a computerized system for the delineation of upper airway structures via MRI and to evaluate its effectiveness for routine clinical use in aiding diagnosis of upper airway disorders in children. We use two MRI protocols, axial T1 and T2, to gather information about different aspects of the airway and its surrounding soft tissue structures including adenoid, tonsils, tongue and soft palate. These images are processed and segmented to compute the architectural parameters of the airway such as its surface description, volume, central (medial) line, and cross-sectional areas at planes orthogonal to the central line. We have built a software package based on 3DVIEWNIX and running on a 450 MHz Pentium PC under Linux system (and on a Sun workstation under Unix) for the various operations of visualization, segmentation, registration, prefiltering, interpolation, standardization, and quantitative analysis of the airway. The system has been tested utilizing 40 patient studies. For every study, the system segmented and displayed a smooth 3D rendition of the airway, its central line and a plot of the cross-sectional area of the airway orthogonal to the central line as a function of the distance from one end of the central line. The tests indicate 97% precision and accuracy for segmentation. The mean time taken per study is about 4 minutes for the airway. This includes operator interaction time and processing time. This method provides a robust and fast means of assessing the airway size, shape, and places of restriction, as well as providing a structural data set suitable for use in modeling studies of airflow and mechanics.
data sets from large-scale simulations (up to 501/sup 3/ grid points) of mantle convection are analyzed with volume rendering of the temperature field and a new critical point analysis of the velocity field. As the Ra...
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data sets from large-scale simulations (up to 501/sup 3/ grid points) of mantle convection are analyzed with volume rendering of the temperature field and a new critical point analysis of the velocity field. As the Rayleigh number Ra is increased the thermal field develops increasingly thin plume-like structures along which heat is convected. These eventually break down and become turbulent. visualization methods are used to distinguish between various models of heat conductivity and to develop an intuitive understanding of the structure of the flow.
In this paper attention is focused on visualization and animation of the time and space evaluation of electromagnetic fields radiated and scattered by, simple, wire structures under pulse excitation. For obtaining dis...
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In this paper attention is focused on visualization and animation of the time and space evaluation of electromagnetic fields radiated and scattered by, simple, wire structures under pulse excitation. For obtaining distribution of electromagnetic fields, FDTD technique was employed. For visualization and animation the numerical results, Mathematica of the Wolfram Research and PowerPoint were employed, respectively. That kind of representation of the results may be very helpful for understanding transient electromagnetic phenomena.
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