scholarly journals About grid generation in constructions bounded by the surfaces of revolution

2021 ◽  
Vol 2099 (1) ◽  
pp. 012018
Author(s):  
Natalya A Artyomova ◽  
Olga V Ushakova
Keyword(s):  
Three Dimensional ◽  
Grid Generation ◽  
Optimality Criteria ◽  
Surfaces Of Revolution ◽  
Basic Construction ◽  
Structured Grid ◽  
Current State ◽  
Straight Line ◽  
Parallel Axis ◽  
Optimal Grids

Abstract For constructions bounded by the surfaces of revolution, structured grid generation technique is presented. Its technology has been elaborated within the variational approach for constructing optimal grids satisfying optimality criteria: closeness of grids to uniform ones, closeness of grids to orthogonal ones and adaptation to a given function. Grid generation has been designed for numerical solution of the differential equations modeling the vortex processes of multi-component hydrodynamics. In the technology, the three-dimensional construction in which it is required to construct a grid is represented in the form of the curvilinear hexahedron defining its configuration. The specific feature of the required configurations is that some faces of a curvilinear hexahedron lie in one plane and along edges of adjoining faces grid cells degenerate into prisms. Grid generation in the considered constructions has started to be developed by the elaboration of algorithms for the volume of revolution which has become the basic construction. The basic construction is obtained by the rotation through 180? around the axis of a generatrix consisting of straight line segments, arcs of circles and ellipses. Then the deformed volumes of revolutions are considered along with the generalizations of the volume of revolution which represent constructions obtained by the surfaces of revolution with parallel axis of rotation. The aim of the further development of the technology is to consider more and more complicated constructions and elaborate the technology for them. In the presentation, the current state of the development of the technology is given. Examples of generated grids are supplied.

PADRAM: Parametric Design and Rapid Meshing System for Turbomachinery Optimisation

2003 ◽  
Author(s):  
Shahrokh Shahpar ◽  
Leigh Lapworth
Keyword(s):  
Parametric Design ◽  
Three Dimensional ◽  
Grid Generation ◽  
Optimization Process ◽  
Design System ◽  
Two Dimensional ◽  
Generation System ◽  
Design Optimisation ◽  
Structured Grid ◽  
Turbomachinery Blades

A parametric design system suitable for inclusion in an automatic optimization process is presented. The system makes use of a multi-block structured grid generation system specially designed for the rapid meshing of two-dimensional, quasi-three-dimensional, and three-dimensional single passage as well as multi-passage, multi-row turbomachinery blades. Full annulus viscous meshes of the order of five to ten million mesh points for the complete bypass assembly of the low pressure compression (LPC) system can be generated in a matter of minutes. PADRAM offers a major new design capability where the optimisation of multi-passage three-dimensional blades and its circumferential pattern is done simultaneously in one system. Successful usage of PADRAM in a number of design, optimisation and analysis applications has recently been demonstrated and reported herein.

Casimir forces and vacuum energy

2017 ◽  
Author(s):  
Serge Reynaud ◽  
Astrid Lambrecht
Keyword(s):  
Casimir Force ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Thermal Fluctuations ◽  
Model Systems ◽  
Vacuum Field ◽  
Force Measurements ◽  
Casimir Forces ◽  
Current State ◽  
Field Fluctuations

The Casimir force is an effect of quantum vacuum field fluctuations, with applications in many domains of physics. The ideal expression obtained by Casimir, valid for perfect plane mirrors at zero temperature, has to be modified to take into account the effects of the optical properties of mirrors, thermal fluctuations, and geometry. After a general introduction to the Casimir force and a description of the current state of the art for Casimir force measurements and their comparison with theory, this chapter presents pedagogical treatments of the main features of the theory of Casimir forces for one-dimensional model systems and for mirrors in three-dimensional space.

scholarly journals Flowering plant embryos: How did we end up here?

2021 ◽  
Author(s):  
Stefan A. Rensing ◽  
Dolf Weijers
Keyword(s):  
Current Knowledge ◽  
General Structure ◽  
Three Dimensional ◽  
Flowering Plants ◽  
Flowering Plant ◽  
Adult Plant ◽  
Ancestral State ◽  
Evolutionary Trajectory ◽  
Current State ◽  
Plant Embryo

AbstractThe seeds of flowering plants are sexually produced propagules that ensure dispersal and resilience of the next generation. Seeds harbor embryos, three dimensional structures that are often miniatures of the adult plant in terms of general structure and primordial organs. In addition, embryos contain the meristems that give rise to post-embryonically generated structures. However common, flowering plant embryos are an evolutionary derived state. Flowering plants are part of a much larger group of embryo-bearing plants, aptly termed Embryophyta. A key question is what evolutionary trajectory led to the emergence of flowering plant embryos. In this opinion, we deconstruct the flowering plant embryo and describe the current state of knowledge of embryos in other plant lineages. While we are far yet from understanding the ancestral state of plant embryogenesis, we argue what current knowledge may suggest and how the knowledge gaps may be closed.

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