Download or read book Parallel Simulation of Moving Boundary Flow Using Overset Adaptive Cartesian Prism Grids and DES written by and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two major tasks have been undertaken in this year: the development of OverCart- the overset Cartesian/prism grid generator and adaptor, and the enhancement of the flow solver to handle moving overset Cartesian/prism grids. Satisfactory progresses have been made in both tasks, and we are on target and within budget to accomplish all the planned research and development efforts. More specifically, the following activities have been carried out from March 1 to September 30, 2004:1. An extensive effort has been made in making the prism grid generation more robust. A comprehensive literature search was carried out to identity the most recent development in this area, and new algorithms are designed and tested. As a result, the prism grid generation algorithm is much more robust, and was capable of tackling vet) complex geometries; 2. The hole cutting and donor cell finding have been implemented in the OverCart software. Octree-based and ADT tree-based algorithms have been employed to speed up the search operations.

Download or read book Parallel Simulation of Moving Boundary Flow Using Overset Adaptive Cartesian prism Grids and DES written by Zhi Jian Wang and published by . This book was released on 2004 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulation of Moving Boundary Flow Using Overset Adaptive Cartesian Prism Grids and DES written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of improved weapon systems requires better understanding of the complex aerodynamics created by moving boundaries. Carriage and release of conventional weapons from aircraft and aerial refueling fall in this category. The flow problem involving moving boundaries are very challenging to compute because the resultant flow field is intrinsically unsteady. Modeling such flow problems is made even more difficult due to the complex geometries and the highly turbulent nature of the unsteady flows. Under an exploratory grant from the AEOSR, a new simulation environment for moving boundary problems is being developed. This environment is designed to advance the state-of-the-art for moving boundary flow problems in the following areas: I. Improve the solution accuracy and efficiency through the use of overset adaptive Cartesian/prism grids. Key flow features will be automatically captured with solution based grid adaptations; 2. Improve the accuracy for highly turbulent unsteady separated flows encountered in moving boundary problems with a hybrid RANS/LES (Reynolds Averaged Navier Stokes/Large Eddy Simulation) a roach named Detached Eddy Simulation (DES).

Download or read book An Overset Adaptive Cartesian prism Grid Method for Moving Boundary Problems written by Ravishekar Kannan and published by . This book was released on 2005 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Scalable and Adaptive Discretization for Free Surface Incompressible Flow Simulation Using Overlapping Cartesian Grids written by Robert Elliot English and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents a novel method for discretizing the incompressible Navier-Stokes equations. Within numerical simulation, the underlying spatial discretization plays a crucial role in defining the properties of a numerical method. In order to resolve solution features on multiple length scales, adaptive spatial discretizations using unstructured and block structured approaches have been developed. However, while many of these methods have resolved the mathematical issues, scaling these methods to large problems which require the use of large distributed memory systems has been problematic due to issues of domain decomposition and remeshing. Block structured approaches such as Adaptive Mesh Refinement (AMR) and Chimera grid methods have been particularly successful since they allow for accurate fluid-structure interaction and spatial adaptivity. However, their scalability has been limited when applied to more complicated problems due the large number of grids required in AMR methods and the complicated linear systems arising in Chimera methods. This dissertation introduces an overlapping grid method that uses moving and overlapping Cartesian grids with independently specified cell sizes to address adaptivity. Unlike AMR approaches, by allowing the Cartesian patches to be arbitrarily rotated and translated, far fewer patches are necessary to rasterize solid boundaries and flow features. This both improves cache coherency and greatly simplifies domain decomposition. Advection is handled with first and second order accurate semi-Lagrangian schemes in order to alleviate any time step restriction associated with small grid cell sizes. The primary focus of this dissertation, however, is the Poisson discretization used in order to solve the elliptic equation for the Navier-Stokes pressure or that resulting from the temporal discretization of parabolic terms such as viscosity. A novel discretization is introduced where the coupling terms are defined implicitly through the use of a Voronoi diagram computed for a subset of the Cartesian grid cell centers. The resulting Poisson discretization is second order accurate and requires the solution of a symmetric positive definite linear system. Each aspect of the approach is demonstrated independently on test problems in order to show efficacy and convergence before finally addressing a number of common test cases for incompressible flow with stationary and moving solid bodies. The method is then extended to handle two-way coupled fluid structure interaction using a monolithic immersed boundary approach. In order to represent free surfaces the particle level set method is adapted to overlapping grids. The method includes a new treatment for particles near grid boundaries with disparate cell sizes, and strategies to deal with issues of locality in the implementation of the level set and fast marching algorithms resulting from the different bandwidths of valid values near the interface on different grids. The resulting method is capable of simulating problems with solution features on disparate scales while efficiently exploiting distributed computational resources.

Download or read book Flow Simulation on Moving Boundary fitted Grids and Application to Fluid structure Interaction Problems written by Martin Engel and published by . This book was released on 2004 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Moving Overlapping Grids with Adaptive Mesh Refinement for High Speed Reactive and Non reactive Flow written by and published by . This book was released on 2005 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: We consider the solution of the reactive and non-reactive Euler equations on two-dimensional domains that evolve in time. The domains are discretized using moving overlapping grids. In a typical grid construction, boundary-fitted grids are used to represent moving boundaries, and these grids overlap with stationary background Cartesian grids. Block-structured adaptive mesh refinement (AMR) is used to resolve fine-scale features in the flow such as shocks and detonations. Refinement grids are added to base-level grids according to an estimate of the error, and these refinement grids move with their corresponding base-level grids. The numerical approximation of the governing equations takes place in the parameter space of each component grid which is defined by a mapping from (fixed) parameter space to (moving) physical space. The mapped equations are solved numerically using a second-order extension of Godunov's method. The stiff source term in the reactive case is handled using a Runge-Kutta error-control scheme. We consider cases when the boundaries move according to a prescribed function of time and when the boundaries of embedded bodies move according to the surface stress exerted by the fluid. In the latter case, the Newton-Euler equations describe the motion of the center of mass of the each body and the rotation about it, and these equations are integrated numerically using a second-order predictor-corrector scheme. Numerical boundary conditions at slip walls are described, and numerical results are presented for both reactive and non-reactive flows in order to demonstrate the use and accuracy of the numerical approach.

Download or read book Tetrahedral Finite volume Solutions to the Navier Stokes Equations on Complex Configurations written by Neal T. Frink and published by . This book was released on 1998 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of the algorithmic features and capabilities of the unstructured-grid flow solver USM3Dns is presented. This code, along with the tetrahedral grid generator, VGRIDns, is being extensively used throughout the U.S. for solving the Euler and Navier-Stokes equations on complex aerodynamic problems. Spatial discretization is accomplished by a tetrahedral cell-centered finite-volume formulation using Roe's upwind flux difference splitting. The fluxes are limited by either a Superbee or MinMod limiter. Solution reconstruction within the tetrahedral cells is accomplished with a simple, but novel, multidimensional analytical formula. Time is advanced by an implicit backward-Euler time-stepping scheme. Flow turbulence effects are modeled by the Spalart-Allmaras one-equation model, which is coupled with a wall function to reduce the number of cells in the near-wall region of the boundary layer. The issues of accuracy and robustness of USM3Dns Navier-Stokes capabilities are addressed for a flat-plate boundary layer, and a full F-16 aircraft with external stores at transonic speed.

Download or read book Twenty Second Symposium on Naval Hydrodynamics written by National Research Council and published by National Academies Press. This book was released on 2000-03-02 with total page 1039 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Twenty-Second Symposium on Naval Hydrodynamics was held in Washington, D.C., from August 9-14, 1998. It coincided with the 100th anniversary of the David Taylor Model Basin. This international symposium was organized jointly by the Office of Naval Research (Mechanics and Energy Conversion S&T Division), the National Research Council (Naval Studies Board), and the Naval Surface Warfare Center, Carderock Division (David Taylor Model Basin). This biennial symposium promotes the technical exchange of naval research developments of common interest to all the countries of the world. The forum encourages both formal and informal discussion of the presented papers, and the occasion provides an opportunity for direct communication between international peers.

Download or read book Unsteady Computational Fluid Dynamics in Aeronautics written by P.G. Tucker and published by Springer Science & Business Media. This book was released on 2013-08-30 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of Large Eddy Simulation (LES) and hybrids is a vibrant research area. This book runs through all the potential unsteady modelling fidelity ranges, from low-order to LES. The latter is probably the highest fidelity for practical aerospace systems modelling. Cutting edge new frontiers are defined. One example of a pressing environmental concern is noise. For the accurate prediction of this, unsteady modelling is needed. Hence computational aeroacoustics is explored. It is also emerging that there is a critical need for coupled simulations. Hence, this area is also considered and the tensions of utilizing such simulations with the already expensive LES. This work has relevance to the general field of CFD and LES and to a wide variety of non-aerospace aerodynamic systems (e.g. cars, submarines, ships, electronics, buildings). Topics treated include unsteady flow techniques; LES and hybrids; general numerical methods; computational aeroacoustics; computational aeroelasticity; coupled simulations and turbulence and its modelling (LES, RANS, transition, VLES, URANS). The volume concludes by pointing forward to future horizons and in particular the industrial use of LES. The writing style is accessible and useful to both academics and industrial practitioners. From the reviews: "Tucker's volume provides a very welcome, concise discussion of current capabilities for simulating and modellng unsteady aerodynamic flows. It covers the various pos sible numerical techniques in good, clear detail and presents a very wide range of practical applications; beautifully illustrated in many cases. This book thus provides a valuable text for practicing engineers, a rich source of background information for students and those new to this area of Research & Development, and an excellent state-of-the-art review for others. A great achievement." Mark Savill FHEA, FRAeS, C.Eng, Professor of Computational Aerodynamics Design & Head of Power & Propulsion Sciences, Department of Power & Propulsion, School of Engineering, Cranfield University, Bedfordshire, U.K. "This is a very useful book with a wide coverage of many aspects in unsteady aerodynamics method development and applications for internal and external flows." L. He, Rolls-Royce/RAEng Chair of Computational Aerothermal Engineering, Oxford University, U.K. "This comprehensive book ranges from classical concepts in both numerical methods and turbulence modelling approaches for the beginner to latest state-of-the-art for the advanced practitioner and constitutes an extremely valuable contribution to the specific Computational Fluid Dynamics literature in Aeronautics. Student and expert alike will benefit greatly by reading it from cover to cover." Sébastien Deck, Onera, Meudon, France

Download or read book Discontinuous Galerkin Methods written by Bernardo Cockburn and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: A class of finite element methods, the Discontinuous Galerkin Methods (DGM), has been under rapid development recently and has found its use very quickly in such diverse applications as aeroacoustics, semi-conductor device simula tion, turbomachinery, turbulent flows, materials processing, MHD and plasma simulations, and image processing. While there has been a lot of interest from mathematicians, physicists and engineers in DGM, only scattered information is available and there has been no prior effort in organizing and publishing the existing volume of knowledge on this subject. In May 24-26, 1999 we organized in Newport (Rhode Island, USA), the first international symposium on DGM with equal emphasis on the theory, numerical implementation, and applications. Eighteen invited speakers, lead ers in the field, and thirty-two contributors presented various aspects and addressed open issues on DGM. In this volume we include forty-nine papers presented in the Symposium as well as a survey paper written by the organiz ers. All papers were peer-reviewed. A summary of these papers is included in the survey paper, which also provides a historical perspective of the evolution of DGM and its relation to other numerical methods. We hope this volume will become a major reference in this topic. It is intended for students and researchers who work in theory and application of numerical solution of convection dominated partial differential equations. The papers were written with the assumption that the reader has some knowledge of classical finite elements and finite volume methods.

Download or read book New Results in Numerical and Experimental Fluid Mechanics X written by Andreas Dillmann and published by Springer. This book was released on 2016-03-28 with total page 855 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents contributions to the 19th biannual symposium of the German Aerospace Aerodynamics Association (STAB) and the German Society for Aeronautics and Astronautics (DGLR). The individual chapters reflect ongoing research conducted by the STAB members in the field of numerical and experimental fluid mechanics and aerodynamics, mainly for (but not limited to) aerospace applications, and cover both nationally and EC-funded projects. Special emphasis is given to collaborative research projects conducted by German scientists and engineers from universities, research-establishments and industries. By addressing a number of cutting-edge applications, together with the relevant physical and mathematics fundamentals, the book provides readers with a comprehensive overview of the current research work in the field. Though the book’s primary emphasis is on the aerospace context, it also addresses further important applications, e.g. in ground transportation and energy.

Download or read book Grid Generation Methods written by Vladimir D. Liseikin and published by Springer Science & Business Media. This book was released on 2009-10-27 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text is an introduction to methods of grid generation technology in scientific computing. Special attention is given to methods developed by the author for the treatment of singularly-perturbed equations, e.g. in modeling high Reynolds number flows. Functionals of conformality, orthogonality, energy and alignment are discussed.

Download or read book Recent Developments in Discontinuous Galerkin Finite Element Methods for Partial Differential Equations written by Xiaobing Feng and published by Springer Science & Business Media. This book was released on 2013-11-08 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of discontinuous Galerkin finite element methods has attracted considerable recent attention from scholars in the applied sciences and engineering. This volume brings together scholars working in this area, each representing a particular theme or direction of current research. Derived from the 2012 Barrett Lectures at the University of Tennessee, the papers reflect the state of the field today and point toward possibilities for future inquiry. The longer survey lectures, delivered by Franco Brezzi and Chi-Wang Shu, respectively, focus on theoretical aspects of discontinuous Galerkin methods for elliptic and evolution problems. Other papers apply DG methods to cases involving radiative transport equations, error estimates, and time-discrete higher order ALE functions, among other areas. Combining focused case studies with longer sections of expository discussion, this book will be an indispensable reference for researchers and students working with discontinuous Galerkin finite element methods and its applications.

Download or read book Handbook of Thermal Management of Engines written by P. A. Lakshminarayanan and published by Springer Nature. This book was released on 2022-01-01 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook deals with the vast subject of thermal management of engines and vehicles by applying the state of the art research to diesel and natural gas engines. The contributions from global experts focus on management, generation, and retention of heat in after-treatment and exhaust systems for light-off of NOx, PM, and PN catalysts during cold start and city cycles as well as operation at ultralow temperatures. This book will be of great interest to those in academia and industry involved in the design and development of advanced diesel and CNG engines satisfying the current and future emission standards.

Download or read book Anagram Solver written by Bloomsbury Publishing and published by Bloomsbury Publishing. This book was released on 2009-01-01 with total page 719 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anagram Solver is the essential guide to cracking all types of quiz and crossword featuring anagrams. Containing over 200,000 words and phrases, Anagram Solver includes plural noun forms, palindromes, idioms, first names and all parts of speech. Anagrams are grouped by the number of letters they contain with the letters set out in alphabetical order so that once the letters of an anagram are arranged alphabetically, finding the solution is as easy as locating the word in a dictionary.

Download or read book New Foundation in the Sciences written by V. Christianto, F. Smarandache, R.N. Boyd and published by Infinite Study. This book was released on with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is widely known among the Frontiers of physics, that “sweeping under the rug” practice has been quite the norm rather than exception. In other words, the leading paradigms have strong tendency to be hailed as the only game in town.