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Visualization For High Order Dg Computational Fluid Dynamics Results
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Book Synopsis IDIHOM: Industrialization of High-Order Methods - A Top-Down Approach by : Norbert Kroll
Download or read book IDIHOM: Industrialization of High-Order Methods - A Top-Down Approach written by Norbert Kroll and published by Springer. This book was released on 2015-01-02 with total page 683 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes the main findings of the EU-funded project IDIHOM (Industrialization of High-Order Methods – A Top-Down Approach). The goal of this project was the improvement, utilization and demonstration of innovative higher-order simulation capabilities for large-scale aerodynamic application challenges in the aircraft industry. The IDIHOM consortium consisted of 21 organizations, including aircraft manufacturers, software vendors, as well as the major European research establishments and several universities, all of them with proven expertise in the field of computational fluid dynamics. After a general introduction to the project, the book reports on new approaches for curved boundary-grid generation, high-order solution methods and visualization techniques. It summarizes the achievements, weaknesses and perspectives of the new simulation capabilities developed by the project partners for various industrial applications, and includes internal- and external-aerodynamic as well as multidisciplinary test cases.
Book Synopsis Techniques for High-order Adaptive Discontinuous Galerkin Discretizations in Fluid Dynamics by : Li Wang
Download or read book Techniques for High-order Adaptive Discontinuous Galerkin Discretizations in Fluid Dynamics written by Li Wang and published by . This book was released on 2009 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of high-order discontinuous Galerkin (DG) discretizations has become more widespread over the last decade for solving convection-dominated computational fluid dynamics problems. The appeal of these methods relates to their favorable asymptotic accuracy properties, combined with compact stencils and favorable scalability properties on parallel computing architectures. This work covers advances in several areas of high-order DG discretizations, including the development of implicit solvers, discrete adjoint methods for shape optimization, and output-based error estimation and mesh and time-step adaptation. For time-dependent problems, high-order implicit time-integration schemes are considered exclusively to avoid the stability restrictions of explicit methods, with particular emphasis on balancing spatial and temporal accuracy of the overall approach. In order to make the high-order schemes competitive, efficient solution techniques consisting of a p -multigrid approach driven by element Jacobi smoothers are investigated and developed to accelerate convergence of the non-linear systems, in which the results demonstrate h independent convergence rates, while remaining relatively insensitive to time-step sizes. A framework based on discrete adjoint sensitivity analysis has also been developed for applications in shape optimization and goal-oriented error estimation. An adaptive discontinuous Galerkin algorithm driven by an adjoint-based error estimation procedure has been developed, which incorporates both h-, p- and combined hp -adaptive schemes, for producing accurate simulations at optimal cost in the objective functional of interest. Current results show superior performance of these adaptive schemes over uniform mesh refinement methods, as well as the potential of the hp refinement approach to capture strong shocks without limiters. Finally, the adjoint-based error estimation strategy is successfully extended to unsteady flow problems, where the time-dependent flow solution is solved in a forward manner in time but the corresponding unsteady adjoint solution is evaluated as a backward time integration. Results demonstrate that this methodology provides accurate global temporal error prediction, and may be employed to drive an adaptive time-step refinement strategy for improving the accuracy of specified time-dependent functionals of interest.
Book Synopsis Visualization in Computational Fluid Dynamics: A Case Study by :
Download or read book Visualization in Computational Fluid Dynamics: A Case Study written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The data produced by Computational Fluid Dynamics (CFD) codes creates many problems for visualization systems. The data is volumetric; in other words, the information of interest is throughout a volume and not just on a surface. This volume may be broken up in many different ways. The simplest form of discretization is to cut the volume into a structured set of hexahedra. On the other extreme the volume may be broken into tetrahedra in an irregular manner producing an "unstructured" grid. CFD applications can also produce very large data sets. For example, it is not uncommon to perform a full airplane calculation with over a million nodes. Also, researchers are now looking at 3D CFD calculations that are time varyingZ Traditional visualization techniques based on CAD output only provide surface information and cannot give the CFD investigator much help in quickly understanding the results of these codes. Within the last couple of years graphics workstations have advanced to the point where the high-end workstations, due to their speed in both "number-crunching" and 3D drawing capabilities, are appropriate for interactive volumetric scientific visualization. VISUAL312 was written to take advantage of these workstations in tackling the problems of investigating the results from CFD calculations.
Book Synopsis Flow Visualization by : Alexander J. Smits
Download or read book Flow Visualization written by Alexander J. Smits and published by World Scientific. This book was released on 2012 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the 2nd edition of the book, Flow Visualization: Techniques and Examples, which was published by Imperial College Press in 2000. Many of the chapters have been revised and updated to take into consideration recent changes in a number of flow visualization and measurement techniques, including an updated high quality flow gallery. Unique among similar publications, this book focuses on the practical rather than theoretical aspects. Obtaining high quality flow visualization results is, in many ways, more of an art than a science, and experience plays a key deciding role. The depth and breadth of the material will make this book invaluable to readers of all levels of experience in the field.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722937836 Total Pages :42 pages Book Rating :4.9/5 (378 download)
Book Synopsis Visualization of Unsteady Computational Fluid Dynamics by : National Aeronautics and Space Administration (NASA)
Download or read book Visualization of Unsteady Computational Fluid Dynamics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-15 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current compute environment that most researchers are using for the calculation of 3D unsteady Computational Fluid Dynamic (CFD) results is a super-computer class machine. The Massively Parallel Processors (MPP's) such as the 160 node IBM SP2 at NAS and clusters of workstations acting as a single MPP (like NAS's SGI Power-Challenge array and the J90 cluster) provide the required computation bandwidth for CFD calculations of transient problems. If we follow the traditional computational analysis steps for CFD (and we wish to construct an interactive visualizer) we need to be aware of the following: (1) Disk space requirements. A single snap-shot must contain at least the values (primitive variables) stored at the appropriate locations within the mesh. For most simple 3D Euler solvers that means 5 floating point words. Navier-Stokes solutions with turbulence models may contain 7 state-variables. (2) Disk speed vs. Computational speeds. The time required to read the complete solution of a saved time frame from disk is now longer than the compute time for a set number of iterations from an explicit solver. Depending, on the hardware and solver an iteration of an implicit code may also take less time than reading the solution from disk. If one examines the performance improvements in the last decade or two, it is easy to see that depending on disk performance (vs. CPU improvement) may not be the best method for enhancing interactivity. (3) Cluster and Parallel Machine I/O problems. Disk access time is much worse within current parallel machines and cluster of workstations that are acting in concert to solve a single problem. In this case we are not trying to read the volume of data, but are running the solver and the solver outputs the solution. These traditional network interfaces must be used for the file system. (4) Numerics of particle traces. Most visualization tools can work upon a single snap shot of the data but some visualization tools for transient problems...
Book Synopsis Optimizing Particle-based Flow Visualization by : Alexy Agranovsky
Download or read book Optimizing Particle-based Flow Visualization written by Alexy Agranovsky and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Within both the scientific and academic communities, the study and visualization of flow is an essential tool used to model fluid transport and mixing. Modern Computational Fluid Dynamics (CFD) simulations are used to successfully approximate real-world physics to reproduce dynamic flow behavior, however, from simulation to visualization, maintaining a high level of accuracy is fraught with obstacles. In this thesis, we address two major challenges to visualizing fluid flow data accurately. The first challenge, encountered during the simulation stage, is the inability of supercomputers to allow simulations to be saved at their native resolution. The second challenge, confronted in the post-processing stage, involves combating the substantial and discouraging computational expense associated with highly accurate particle-based visualization techniques. We begin by presenting a framework for detecting and accumulating flow characteristics during the particle advection process, aimed at optimizing the associated computational burden. Consequently, we provide evidence of a wealth of fluid flow knowledge that can be gained with little computational overhead. We then extend the detection of these flow transformation effects to the simulation stage, offering a novel compression algorithm designed to dynamically distribute the constrained budget set when writing simulation results to disk. The output focuses on flow deformation and rotation, thereby improving visualization accuracy in turbulent regions. Next, we describe the versatility of interpolation as a substitute for costly and iterative numerical integration. We present a method for categorizing salient flow features using only a sub- set of advected particles to interpolate the remaining domain information. Overall, the number of advection steps is drastically cut down and our method is able to better visualize features of interest with fewer particles. Building on this work, we eliminate advection entirely and develop an inter- active exploration environment based solely on interpolating trajectory position information. After achieving positive results in the visualization stage, we further explore the Lagrangian representation - a dense sampling of the flow field with particle trajectories - as an alternative output to CFD simulations. Through a series of comprehensive tests, we verify that the Lagrangian representation is less sensitive than traditional output to the unavoidable temporal compression that occurs when writing to disk. Subsequently, we demonstrate that particle trajectories extracted during the post- processing stage are more accurate, with the added benefit of increased performance and less disk space usage necessary to store the simulation output itself. The primary objective of our work is to advance the field of flow visualization, focusing on the challenges that arise when high accuracy is required. With CFD simulations growing ever more complex and many scientists within academia and industry turning to flow visualization, we provide solutions to help retain flow field accuracy while optimizing both the storage of simulation data on disk and the computational expense of particle-based visualization techniques.
Download or read book Computational Fluid Dynamics written by and published by . This book was released on 1992 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Visualization and Approximation of Post Processed Computational Fluid Dynamics Data in a Virtual Environment by : Vishant Jude Shahnawaz
Download or read book Visualization and Approximation of Post Processed Computational Fluid Dynamics Data in a Virtual Environment written by Vishant Jude Shahnawaz and published by . This book was released on 2000 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational fluid dynamics (CFD) data is obtained as a result of numerical analysis performed on a flow model. In order for this data to be accurately analyzed, it is necessary to be able to visualize it in 3-D space. While visualizing this data, engineers sometimes find it necessary to visualize changes in the characteristics of the flow with respect to changes in the value of certain input parameters. However, generating CFD data sets for several values of input parameters is a tedious procedure, and cannot be done interactively. This thesis proposes a method where approximations between data sets are used instead of resolving the entire CFD model so that interaction with the data can be performed interactively. There are three parts to this thesis. The first part describes the methodology and features of visualizing the data in a virtual environment through the interactive creation and manipulation of flow entities such as streamlines, cutting planes, and isosurfaces. The second part of the thesis analyzes two methods of approximation on large data sets. The third part describes the actual interactive implementation of the approximation methods in a full-scale application. The methods used here are the Virtual knot technique of B-spline curve fitting and basic linear interpolation. The input parameters, that are being varied, are the geometrical attributes of the data set. The application was developed using OpenGL and the Visualization Toolkit (VTK) libraries for the rendering and visualization calculations. In addition, the C2 interface libraries were used to create the Virtual Reality environment.
Book Synopsis TILDA: Towards Industrial LES/DNS in Aeronautics by : Charles Hirsch
Download or read book TILDA: Towards Industrial LES/DNS in Aeronautics written by Charles Hirsch and published by Springer Nature. This book was released on 2021-06-28 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers detailed insights into new methods for high-fidelity CFD, and their industrially relevant applications in aeronautics. It reports on the H2020 TILDA project, funded by the European Union in 2015-2018. The respective chapters demonstrate the potential of high-order methods for enabling more accurate predictions of non-linear, unsteady flows, ensuring enhanced reliability in CFD predictions. The book highlights industrially relevant findings and representative test cases on the development of high-order methods for unsteady turbulence simulations on unstructured grids; on the development of the LES/DNS methodology by means of multilevel, adaptive, fractal and similar approaches for applications on unstructured grids; and on leveraging existent large-scale HPC networks to facilitate the industrial applications of LES/DNS in daily practice. Furthermore, the book discusses multidisciplinary applications of high-order methods in the area of aero-acoustics. All in all, it offers timely insights into the application and performance of high-order methods for CFD, and an extensive reference guide for researchers, graduate students, and industrial engineers whose work involves CFD and turbulence modeling.
Book Synopsis Development of High-order Discontinuous Galerkin Methods for Simulations of High-speed Particle-laden Fluid Flows by : Eric Jishuan Ching
Download or read book Development of High-order Discontinuous Galerkin Methods for Simulations of High-speed Particle-laden Fluid Flows written by Eric Jishuan Ching and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An encouraging alternative to conventional finite-volume and finite-difference schemes for computational fluid dynamics is the discontinuous Galerkin (DG) method. This method combines aspects of finite-element and finite-volume schemes, employing piecewise polynomials to approximate the solution. It offers a number of advantages, such as arbitrarily high order of accuracy with a compact stencil on unstructured meshes. Furthermore, it is well-suited for advanced mesh adaptation strategies and can achieve great efficiency on graphics processing units (GPUs). However, there are several challenges as well. One of these is the robust capturing of shocks and other flow-field discontinuities. In addition, compared to more mature numerical methods, the DG scheme lacks a well-established infrastructure for handling complex physics, such as particle-laden flows. In light of this, the overarching objective of this work is to develop a DG framework for simulating high-speed particle-laden fluid flows and then apply the resulting methodology to investigate hypersonic dusty flows over blunt bodies, with special focus on Mars atmospheric entry. A simple and robust shock capturing method is first developed. The method employs intra-element variations for shock detection and smooth artificial viscosity for stabilization. We apply the shock capturing method to compute canonical hypersonic test cases, such as flows over a cylinder and a double cone. Quantitative comparisons with state-of-the-art finite-volume codes demonstrate significant benefits of the proposed DG formulation for hypersonic flow computations. In particular, in contrast with finite-volume techniques, the DG method can accurately predict surface heating with strong mesh-shock alignment and with fewer degrees of freedom. We then develop a methodology for simulating particle-laden flows with the DG scheme. The particles are described in a Lagrangian manner. The use of curved elements, which are necessary in high-order DG simulations involving curved geometries, presents significant challenges for tracking and localizing the particles on the Eulerian mesh. We propose strategies to handle particle-wall collisions on arbitrary curved, high-aspect-ratio elements, and we find that curved elements can significantly improve predictions of particle trajectories. In addition, an algorithm is developed for treating interparticle collisions that exploits the geometric mapping from physical space to reference space. The algorithm can significantly reduce computational cost compared to conventional strategies. We also develop smooth anisotropic kernels for projecting the effect of the particle phase onto the Eulerian mesh in a robust, accurate, and efficient manner, particularly on high-aspect-ratio elements. Simulations of shock-particle interaction, sandblasting, and other applications illustrate the ability of the developed algorithms to effectively compute complex multiphase flows. Finally, we apply the resulting Euler-Lagrange methodology to compute hypersonic dusty flows over blunt bodies. To address the overall lack of high-quality experimental data, a parametric study is conducted to investigate the sensitivities of the solution to the physical modeling of the particle phase. We also simulate dusty flows over the full-scale ExoMars Schiaparelli capsule at realistic flow conditions. Detailed analysis of particle trajectories through the shock layer is performed. The effects of the dust particles on heat shields, such as heat flux augmentation and surface recession, are characterized.
Book Synopsis Fluid Mechanics Applied to Medicine by : Alberto Pozo Álvarez
Download or read book Fluid Mechanics Applied to Medicine written by Alberto Pozo Álvarez and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book aims to show how hemodynamic numerical models based on Computational Fluid Dynamics (CFD) can be developed. An approach to Fluid Mechanics is made from a historical point of view focusing on the Navier-Stokes Equations and a fluid-mechanical description of blood flow. Finally, the techniques most used to visualize cardiac flows and validate numerical models are detailed, paying special attention to Magnetic Resonance Imaging (MRI) in case of an in vivo validation and Particle Image Velocimetry (PIV) for an in vitro validation.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 994 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High Performance Computing in Science and Engineering ́15 by : Wolfgang E. Nagel
Download or read book High Performance Computing in Science and Engineering ́15 written by Wolfgang E. Nagel and published by Springer. This book was released on 2016-02-05 with total page 701 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS) in 2015. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance. The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of color illustrations and tables of results.
Book Synopsis Direct and Large-Eddy Simulation IX by : Jochen Fröhlich
Download or read book Direct and Large-Eddy Simulation IX written by Jochen Fröhlich and published by Springer. This book was released on 2015-01-27 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reflects the state of the art of numerical simulation of transitional and turbulent flows and provides an active forum for discussion of recent developments in simulation techniques and understanding of flow physics. Following the tradition of earlier DLES workshops, these papers address numerous theoretical and physical aspects of transitional and turbulent flows. At an applied level it contributes to the solution of problems related to energy production, transportation, magneto-hydrodynamics and the environment. A special session is devoted to quality issues of LES. The ninth Workshop on 'Direct and Large-Eddy Simulation' (DLES-9) was held in Dresden, April 3-5, 2013, organized by the Institute of Fluid Mechanics at Technische Universität Dresden. This book is of interest to scientists and engineers, both at an early level in their career and at more senior levels.
Book Synopsis Adaptive High-order Methods in Computational Fluid Dynamics by : Z. J. Wang
Download or read book Adaptive High-order Methods in Computational Fluid Dynamics written by Z. J. Wang and published by World Scientific. This book was released on 2011 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of important contributions by world-renowned experts on adaptive high-order methods in computational fluid dynamics (CFD). It covers several widely used, and still intensively researched methods, including the discontinuous Galerkin, residual distribution, finite volume, differential quadrature, spectral volume, spectral difference, PNPM, and correction procedure via reconstruction methods. The main focus is applications in aerospace engineering, but the book should also be useful in many other engineering disciplines including mechanical, chemical and electrical engineering. Since many of these methods are still evolving, the book will be an excellent reference for researchers and graduate students to gain an understanding of the state of the art and remaining challenges in high-order CFD methods.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722733629 Total Pages :24 pages Book Rating :4.7/5 (336 download)
Book Synopsis Research in Computational Fluid Dynamics and Analysis of Algorithms by : National Aeronautics and Space Administration (NASA)
Download or read book Research in Computational Fluid Dynamics and Analysis of Algorithms written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, higher-order compact schemes have seen increasing use in the DNS (Direct Numerical Simulations) of the Navier-Stokes equations. Although they do not have the spatial resolution of spectral methods, they offer significant increases in accuracy over conventional second order methods. They can be used on any smooth grid, and do not have an overly restrictive CFL dependence as compared with the O(N(exp -2)) CFL dependence observed in Chebyshev spectral methods on finite domains. In addition, they are generally more robust and less costly than spectral methods. The issue of the relative cost of higher-order schemes (accuracy weighted against physical and numerical cost) is a far more complex issue, depending ultimately on what features of the solution are sought and how accurately they must be resolved. In any event, the further development of the underlying stability theory of these schemes is important. The approach of devising suitable boundary clusters and then testing them with various stability techniques (such as finding the norm) is entirely the wrong approach when dealing with high-order methods. Very seldom are high-order boundary closures stable, making them difficult to isolate. An alternative approach is to begin with a norm which satisfies all the stability criteria for the hyperbolic system, and look for the boundary closure forms which will match the norm exactly. This method was used recently by Strand to isolate stable boundary closure schemes for the explicit central fourth- and sixth-order schemes. The norm used was an energy norm mimicking the norm for the differential equations. Further research should be devoted to BC for high order schemes in order to make sure that the results obtained are reliable. The compact fourth order and sixth order finite difference scheme had been incorporated into a code to simulate flow past circular cylinders. This code will serve as a verification of the full spectral codes. A detailed stability analysis by...
Book Synopsis Interactive Visualization of Computational Fluid Dynamics Data by : Zhenmin Peng
Download or read book Interactive Visualization of Computational Fluid Dynamics Data written by Zhenmin Peng and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
