scholarly journals New Computational Geometry Methods Applied to Solve Complex Problems of Radiative Transfer

Mathematics ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 2176
Author(s):  
Francisco Salguero-Andújar ◽  
Joseph-Maria Cabeza-Lainez
Keyword(s):  
Radiative Transfer ◽  
Computational Geometry ◽  
Energy Exchange ◽  
Solid Angle ◽  
Computer Time ◽  
Acoustic Energy ◽  
Innovative Approach ◽  
Graphical Interface ◽  
Aided Design ◽  
Cumbersome Calculation

Diverse problems of radiative transfer remain as yet unsolved due to the difficulties of the calculations involved, especially if the intervening shapes are geometrically complex. The main goal of our investigation in this domain is to convert the equations that were previously derived into a graphical interface based on the projected solid-angle principle. Such a procedure is now feasible by virtue of several widely diffused programs for Algorithms Aided Design (AAD). Accuracy and reliability of the process is controlled in the basic examples by means of subroutines from the analytical software DianaX, developed at an earlier stage by the authors, though mainly oriented to closed cuboidal or curved volumes. With this innovative approach, the often cumbersome calculation procedure of lighting, thermal or even acoustic energy exchange can be simplified and made available for the neophyte, with the undeniable advantage of reduced computer time.

scholarly journals New Computational Geometry Methods Applied to Solve Complex Problems of Radiative Transfer

2020 ◽  
Author(s):  
Francisco Salguero-Andújar ◽  
Joseph Cabeza-Lainez
Keyword(s):  
Radiative Transfer ◽  
Computational Geometry ◽  
Solid Angle ◽  
Computer Time ◽  
Graphical Interface ◽  
New Approach ◽  
Thermal Exchange ◽  
Complex Problems ◽  
Geometrically Complex ◽  
Aided Design

Several problems of radiative transfer are yet unsolved because of the difficulties of the calculations involved in them, especially if the intervening shapes are geometrically complex. The main goal of our investigation in this domain is to convert the formulas that were previously derived, into a graphical interface based on the projected solid-angle principle. Such procedure is now feasible by virtue of several widely diffused programs for Algorithms Aided Design (AAD). Accuracy and reliability of the process is controlled by means of the analytical software DianaX developed at an earlier stage by the authors. With this new approach the often cumbersome procedure of lighting and thermal exchange calculations can be simplified and made available for the neophyte, with the undeniable advantage of reduced computer time.

scholarly journals Computer-Aided Sketching: Incorporating the Locus to Improve the Three-Dimensional Geometric Design

Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1181 ◽  
Author(s):  
José Ignacio Rojas-Sola ◽  
David Hernández-Díaz ◽  
Ricardo Villar-Ribera ◽  
Vicente Hernández-Abad ◽  
Francisco Hernández-Abad
Keyword(s):  
Computational Geometry ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Geometric Design ◽  
Curved Surfaces ◽  
Two Dimensional ◽  
Technical Design ◽  
Computer Aided ◽  
Aided Design

This article presents evidence of the convenience of implementing the geometric places of the plane into commercial computer-aided design (CAD) software as auxiliary tools in the computer-aided sketching process. Additionally, the research considers the possibility of adding several intuitive spatial geometric places to improve the efficiency of the three-dimensional geometric design. For demonstrative purposes, four examples are presented. A two-dimensional figure positioned on the flat face of an object shows the significant improvement over tools currently available in commercial CAD software, both vector and parametric: it is more intuitive and does not require the designer to execute as many operations. Two more complex three-dimensional examples are presented to show how the use of spatial geometric places, implemented as CAD software functions, would be an effective and highly intuitive tool. Using these functions produces auxiliary curved surfaces with points whose notable features are a significant innovation. A final example provided solves a geometric place problem using own software designed for this purpose. The proposal to incorporate geometric places into CAD software would lead to a significant improvement in the field of computational geometry. Consequently, the incorporation of geometric places into CAD software could increase technical-design productivity by eliminating some intermediate operations, such as symmetry, among others, and improving the geometry training of less skilled users.

A Computational Geometry for the Blades and Internal Flow Channels of Centrifugal Compressors

1983 ◽  
Vol 105 (2) ◽  
pp. 288-295 ◽  
Author(s):  
M. V. Casey
Keyword(s):  
Computational Geometry ◽  
Computer Aided Design ◽  
Design Procedure ◽  
Internal Flow ◽  
Geometrical Shape ◽  
Parametric Form ◽  
Centrifugal Compressors ◽  
Flow Channels ◽  
Computer Aided ◽  
Aided Design

A new computational geometry for the blades and flow passages of centrifugal compressors is described and examples of its use in the design of industrial compressors are given. The method makes use of Bernstein-Bezier polynomial patches to define the geometrical shape of the flow channels. This has the following main advantages: the surfaces are defined by analytic functions which allow systematic and controlled variation of the shape and give continuous derivatives up to any required order: and the parametric form of the equations allows the blade and channel coordinates to be very simply obtained at any number of points and in any suitable distribution for use in subsequent aerodynamic and stress calculations and for manufacture. The method is particularly suitable for incorporation into a computer-aided design procedure.

Acoustic energy exchange in compressible turbulence

1995 ◽  
Vol 7 (7) ◽  
pp. 1732-1742 ◽  
Author(s):  
Hideaki Miura ◽  
Shigeo Kida
Keyword(s):  
Energy Exchange ◽  
Acoustic Energy ◽  
Compressible Turbulence

Computer-aided design of building structures—a guide to data center service in Canada

1979 ◽  
Vol 6 (3) ◽  
pp. 472-480
Author(s):  
Daniel J. Carson ◽  
Gilbert A. Hartley
Keyword(s):  
Data Center ◽  
Computer Aided Design ◽  
Data Centers ◽  
Computer Time ◽  
Application Software ◽  
Building Structures ◽  
Good Service ◽  
Few Data ◽  
Aided Design ◽  
Center Service

The service available from data centers to structural consultants engaged in the design of buildings is reviewed here. This review includes the main hardware provided by the centers, the application software available, and some comments on the support offered for their application software. This information was obtained by purchasing computer time from data centers in the Ottawa area and using their computer programs in hypothetical design situations. This was supplemented by interviews with data center representatives and a study of brochures and manuals published by the data centers. Although the service available is not of consistently high quality right across the board, there are a few data centers that do offer good service to their engineering clients.

Theory of Radiative Transfer

1989 ◽  
Author(s):  
R. M. Goody ◽  
Y. L. Yung
Keyword(s):  
Radiative Transfer ◽  
Wavelength Range ◽  
Unit Area ◽  
Solid Angle ◽  
Unit Vector ◽  
Small Element ◽  
Frequency Range ◽  
Specific Intensity ◽  
Intensity Field ◽  
The Given

In common with astrophysical usage the word intensity will denote specific intensity of radiation, i.e., the flux of energy in a given direction per second per unit frequency (or wavelength) range per unit solid angle per unit area perpendicular to the given direction. In Fig. 2.1 the point P is surrounded by a small element of area dπs, perpendicular to the direction of the unit vector s. From each point on dπs a cone of solid angle dωs is drawn about the s vector. The bundle of rays, originating on dπs, and contained within dωs, transports in time dt and in the frequency range v to v + dv, the energy . . . Ev = Iv(P,S) dπs dωs dv dt, (2.1). . . where Iv(P, s) is the specific intensity at the point P in the s-direction. If Iv is not a function of direction the intensity field is said to be isotropic ; if Iv is not a function of position the field is said to be homogeneous.

A Computational Geometry for the Blades and Internal Flow Channels of Centrifugal Compressors

1982 ◽  
Author(s):  
M. V. Casey
Keyword(s):  
Computational Geometry ◽  
Computer Aided Design ◽  
Design Procedure ◽  
Internal Flow ◽  
Geometrical Shape ◽  
Parametric Form ◽  
Centrifugal Compressors ◽  
Flow Channels ◽  
Computer Aided ◽  
Aided Design

A new computational geometry for the blades and internal flow passages of centrifugal compressors is described and examples of its use in the design of industrial compressors are given. The method makes use of Bernstein-Bezier polynomial patches to define the geometrical shape of the flow channels. This has the following main advantages: the surfaces are defined by analytic functions which allow systematic and controlled variation of the shape and give continuous derivatives up to any required order; and the parametric form of the equations allows the blade and channel coordinates to be very simply obtained at any number of points and in any suitable distribution for use in subsequent aerodynamic and stress calculations and for manufacture. The method is particularly suitable for incorporation into a computer aided design procedure.

Eliciting User Perceptions Using Assessment Tests Based on an Interactive Genetic Algorithm

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Emilie Poirson ◽  
Jean-François Petiot ◽  
Ludivine Boivin ◽  
David Blumenthal
Keyword(s):  
Genetic Algorithm ◽  
Product Innovation ◽  
Computer Aided Design ◽  
Graphical Interface ◽  
User Perception ◽  
Interactive Genetic Algorithm ◽  
User Perceptions ◽  
Tuning Parameters ◽  
Assessment Tests ◽  
Aided Design

To avoid failures in the marketplace, the control of the risks in product innovation and the reduction of the innovation cycles require fast and valid assessments from customers. An interactive genetic algorithm (IGA) is proposed for eliciting users' perceptions about the shape of a product, in order to stimulate creativity and to identify design trends. Interactive users' assessment tests are conducted on virtual products to capture and analyze users' responses. The IGA is interfaced with Computer Aided Design (CAD) software (CATIA V5) to create sets of parameterized designs in real time, which are presented iteratively by a graphical interface to the users for evaluation. After a description of the IGA, a study on the convergence of the IGA is presented. The convergence varies, according to the tuning parameters of the algorithm and the size of the design problem. An experiment was carried out with a set of 45 users on the application case, a dashboard, put forward by Renault. The implementation of the perceptive tests and the analysis of the results are described using hierarchical ascendant classification (HAC) and multivariate analysis. This paper shows how the results of tests using IGA can be used to elicit user perception and to detect design trends.

scholarly journals ON INCREASING THE EFFICIENCY OF A DISCRETE ORDINATES RADIATIVE TRANSFER METHOD WITH PERIODIC RELATIONS

2005 ◽  
Vol 4 (2) ◽  
pp. 181
Author(s):  
M. P. De Abreu
Keyword(s):  
Radiative Transfer ◽  
Computer Time ◽  
Anisotropic Scattering ◽  
Discrete Ordinates ◽  
Coupling Coefficients ◽  
Radiation Beam ◽  
Component Method ◽  
Two Component ◽  
Transfer Method ◽  
Transfer Problems

In this article, improvements in a recently developed discrete ordinates method – the two-component method - are reported. The method solves conservative and non-conservative radiative heat transfer problems with anisotropic scattering on a multislab domain irradiated from one side with a radiation beam. The beam here consists of a monodirectional (singular) stream and of a continuous (regular) distribution in angle. Specifically, the computational efficiency of this two-component method has been increased with the help of new periodic relations for the coupling coefficients that appear in the numerical component of the method. With these periodic relations, memory usage requirement for storing the (usually large number of) coupling coefficients has been halved, while saving computer time from unnecessary computation of redundant coefficients. The increased efficiency of the two-component method has been illustrated with numerical results and discussion of a model problem in shortwave radiative transfer.

scholarly journals GENERATION OF 3D SHAPES WITH SUPERELLIPSOIDS, SUPERTOROIDS, SUPER CYLINDERS AND SUPER CONES

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
D.L. ŞTEFAN ŢĂLU
Keyword(s):  
Computational Geometry ◽  
Computer Aided Design ◽  
Geometric Constructions ◽  
Geometric Information ◽  
3D Objects ◽  
Computer Aided ◽  
Aided Design ◽  
3D Shapes

<p>The purpose of this paper is to present a CAD study for generating of 3D shapes with superellipsoids, supertoroids, super cylinders and super cones based on computational geometry. To obtain the relevant geometric information concerning the shape and profile for different 3D objects the Madsie Freestyle 1.5.3 application was used. Results from this study are applied in geometric constructions and computer aided design used in engineering and sculpture design.</p>

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