Download or read book Three Dimensional Self Adaptive Grid Method for Complex Flows written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-13 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A self-adaptive grid procedure for efficient computation of three-dimensional complex flow fields is described. The method is based on variational principles to minimize the energy of a spring system analogy which redistributes the grid points. Grid control parameters are determined by specifying maximum and minimum grid spacing. Multidirectional adaptation is achieved by splitting the procedure into a sequence of successive applications of a unidirectional adaptation. One-sided, two-directional constraints for orthogonality and smoothness are used to enhance the efficiency of the method. Feasibility of the scheme is demonstrated by application to a multinozzle, afterbody, plume flow field. Application of the algorithm for initial grid generation is illustrated by constructing a three-dimensional grid about a bump-like geometry. Djomehri, M. Jahed and Deiwert, George S. Ames Research Center ...
Download or read book Three dimensional Self adaptive Grid Method for Complex Flows written by and published by . This book was released on 1988 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Multidimensional Self Adaptive Grid Code Sage written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the multidimensional self-adaptive grid code SAGE. A two-dimensional version of this code was described in an earlier report by the authors. The formulation of the multidimensional version is described in the first section of this document. The second section is presented in the form of a user guide that explains the input and execution of the code and provides many examples. Successful application of the SAGE code in both two and three dimensions for the solution of various flow problems has proven the code to be robust, portable, and simple to use. Although the basic formulation follows the method of Nakahashi and Deiwert, many modifications have been made to facilitate the use of the self-adaptive grid method for complex grid structures. Modifications to the method and the simplified input options make this a flexible and user-friendly code. The new SAGE code can accommodate both two-dimensional and three-dimensional flow problems. Davies, Carol B. and Venkatapathy, Ethiraj Ames Research Center...
Download or read book Application of a Self adaptive Grid Method to Complex Flows written by and published by . This book was released on 1989 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Application of a Self Adaptive Grid Method to Complex Flows written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-25 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A directional-split, modular, user-friendly grid point distribution code is applied to several test problems. The code is self-adaptive in the sense that grid point spacing is determined by user-specified constants denoting maximum and minimum grid spacings and constants relating the relative influence of smoothness and orthogonality. Estimates of truncation error, in terms of flow-field gradients and/or geometric features, are used to determine the point distribution. Points are redistributed along grid lines in a specified direction in an elliptic manner over a user-specified subdomain, while orthogonality and smoothness are controlled in a parabolic (marching) manner in the remaining directions. Multidirectional adaption is achieved by sequential application of the method in each coordinate direction. The flow-field solution is redistributed onto the newly distributed grid points after each unidirectional adaption by a simple one-dimensional interpolation scheme. For time-accurate schemes such interpolation is not necessary and time-dependent metrics are carried in the fluid dynamic equations to account for grid movement. Deiwert, G. S. and Venkatapathy, E. and Davies, C. and Djomehri, J. and Abrahamson, K. Ames Research Center RTOP 506-40-11...
Download or read book The Multidimensional Self Adaptive Grid Code Sage Version 2 written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new report on Version 2 of the SAGE code includes all the information in the original publication plus all upgrades and changes to the SAGE code since that time. The two most significant upgrades are the inclusion of a finite-volume option and the ability to adapt and manipulate zonal-matching multiple-grid files. In addition, the original SAGE code has been upgraded to Version 1.1 and includes all options mentioned in this report, with the exception of the multiple grid option and its associated features. Since Version 2 is a larger and more complex code, it is suggested (but not required) that Version 1.1 be used for single-grid applications. This document contains all the information required to run both versions of SAGE. The formulation of the adaption method is described in the first section of this document. The second section is presented in the form of a user guide that explains the input and execution of the code. The third section provides many examples. Successful application of the SAGE code in both two and three dimensions for the solution of various flow problems has proven the code to be robust, portable, and simple to use. Although the basic formulation follows the method of Nakahashi and Deiwert, many modifications have been made to facilitate the use of the self-adaptive grid method for complex grid structures. Modifications to the method and the simple but extensive input options make this a flexible and user-friendly code. The SAGE code can accommodate two-dimensional and three-dimensional, finite-difference and finite-volume, single grid, and zonal-matching multiple grid flow problems. Davies, Carol B. and Venkatapathy, Ethiraj Ames Research Center...
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1995 with total page 1484 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1995 with total page 1482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three Dimensional Solution Adaptive Grid Generation on Composite Configurations written by Yen Tu and published by . This book was released on 1989 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: A solution-adaptive grid generation procedure is developed and applied to three-dimensional inviscid transonic fluid flow around complex geometries using a composite block grid structure. The adaption is based upon control functions in an elliptic grid generation system. The control function is constructed in a manner such that a proper grid network can be generated as a fluid flow solution is evolving. The grid network is boundary-conforming for accurate representation of boundary conditions. The procedure implemented allows orthogonality at boundaries for more accurate computations, while smoothness is implicit in the elliptic equations. The approach allows multiple-block grid systems to be constructed to treat complex configurations as well. The solution-adaptive computational procedure has been accomplished by coupling the elliptic grid generation technique with an implicit, finite volume, upwind Euler flow solver. In simulating transonic fluid flow around a finned body of revolution and a multiple store configuration, the grid systems adapt to pressure gradients in the flow field. Results obtained show that the technique is capable of generating grid networks proper for the simulations of aerodynamics around complex configurations. Keywords: Computational fluid dynamics, Euler equations. (kr).
Download or read book A Practical Adaptive grid Method for Complex Fluid flow Problems written by and published by . This book was released on 1984 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Tech Briefs written by and published by . This book was released on 1991 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Computational Fluid Dynamics written by Vijay K. Garg and published by CRC Press. This book was released on 1998-05-08 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Describes the latest techniques and real-life applications of computational fluid dynamics (CFD) and heat transfer in aeronautics, materials processing and manufacturing, electronic cooling, and environmental control. Includes new material from experienced researchers in the field. Complete with detailed equations for fluid flow and heat transfer.
Download or read book Sage written by Carol B. Davies and published by BiblioGov. This book was released on 2013-08 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: The multi-dimensional self-adaptive grid code, SAGE, is an important tool in the field of computational fluid dynamics (CFD). It provides an efficient method to improve the accuracy of flow solutions while simultaneously reducing computer processing time. Briefly, SAGE enhances an initial computational grid by redistributing the mesh points into more appropriate locations. The movement of these points is driven by an equal-error-distribution algorithm that utilizes the relationship between high flow gradients and excessive solution errors. The method also provides a balance between clustering points in the high gradient regions and maintaining the smoothness and continuity of the adapted grid, The latest version, Version 3, includes the ability to change the boundaries of a given grid to more efficiently enclose flow structures and provides alternative redistribution algorithms.
Download or read book Numerical Grid Generation in Computational Fluid Mechanics 88 written by S. Sengupta and published by . This book was released on 1988 with total page 1128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications of Mesh Generation to Complex 3 D Configurations written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Specialists' Meeting and published by . This book was released on 1990 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: The AGARD Fluid Dynamics Panel sponsored this Symposium to provide a survey of the capabilities of the CFD community for griding complex 3-D configurations. The intent was to provide some insight to the present state of grid generation for complex configurations to help assess whether this task presents a long-term stumbling block to the routine use of CFD in aerodynamic applications. To this end, the meeting was structured in five sessions: General Surveys, Algebraic Grid Generation, Block Structured Meshes, Multiblock-Adaptive Meshes and Unstructured Meshes. Thwenty-two papers from these sessions amply gemonstrated that the viability of a numerical solution depends directly on the quality of the mesh and surface representation as measured by its spacing and resolution. Of Particular interest was the mesh generation for complex configurations, such as advanced fighter or transport aircraft, missiles and space vehicles, where complex geometries and/or complex flowfields have to be analysed. Results from this meeting indicate that geometry discretization and generation of meshes for complex 3-D configurations in aerospace will continue to be time- and cost-consuming operations fro some time to come.
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1990 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
