Download or read book Efficient High order Accurate Unstructured Finite volume Algorithms for Viscous and Inviscid Compressible Flows written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High-order accurate methods have the potential to dramatically reduce the computational time needed for aerodynamics simulations. This thesis studies the discretization and efficient convergence to steady state of the high-order accurate finite-volume method applied to the simplified problem of inviscid and laminar viscous two-dimensional flow equations. Each of the three manuscript chapters addresses a specific problem or limitation previously experienced with these schemes. The first manuscript addresses the absence of a method to maintain monotonicity of the solution at discontinuities while maintaining high-order accuracy in smooth regions. To resolve this, a slope limiter is carefully developed which meets these requirements while also maintaining the good convergence properties and computational efficiency of the least-squares reconstruction scheme. The second manuscript addresses the relatively poor convergence properties of Newton-GMRES methods applied to high-order accurate schemes. The globalization of the Newton method is improved through the use of an adaptive local timestep and of a line search algorithm. The poor convergence of the linear solver is improved through the efficient assembly of the exact flux Jacobian for use in preconditioning and to eliminate the additional residual evaluations needed by a matrix-free method. The third manuscript extends the discretization method to the viscous fluxes and boundary conditions. The discretization is demonstrated to achieve the expected order of accuracy. The fourth-order scheme is also shown to be more computationally efficient than the second-order scheme at achieving grid-converged values of drag for two-dimensional laminar flow over an airfoil.

Download or read book Computational Fluid Dynamics 2006 written by Herman Deconinck and published by Springer. This book was released on 2016-04-01 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt: ThisbookcontainstheproceedingsoftheFourthInternationalConference onComputationalFluidDynamics(ICCFD4), heldinGent, Belgiumfrom July10through16,2006. TheICCFDconferenceseriesisanoutcomeofthe mergeroftwoimportantstreamsofconferencesinComputationalFluid- namics: InternationalConferenceonNumericalMethodsinFluidDynamics, ICNMFD(since1996)andInternationalSymposiumonComputationalFluid Dynamics, ISCFD(since1985). In1998itwasdecidedtojointhetwoand ICCFD emerged as a biannual meeting, held in Kyoto in 2000, Sydney in 2002, Toronto in 2004 and Gent in 2006. Thus, the ICCFD series became theleadinginternationalconferenceseriesforscientists, mathematiciansand engineersinterestedinthecomputationof?uid?ow. The4theditionoftheconferencehasattracted200participantsfromall overtheworld;270abstractswerereceived, ofwhich135wereselectedina carefulpeerreviewprocessbytheexecutivecommittee(C. H. Bruneau, J. -J. Chattot, D. Kwak, N. Satofuka, D. W. Zingg, E. DickandH. Deconinck)for oralpresentationandafurther21forposterpresentation. Thepaperscontainedintheseproceedingsprovideanexcellentsnapshot of the ?eld of Computational Fluid Dynamics as of 2006. Invited keynote lecturesbyrenownedresearchersareincluded, withcontributionsinthe?eld ofdiscretizationschemes, high-endcomputingandengineeringchallenges, and two-phase?ow. Thesekeynotecontributionsarecomplementedby137regular papersonthemostdiverseaspectsofCFD: -Innovativealgorithmdevelopmentfor?owsimulation, optimisationandc- trol: higher-ordermethods(DG, FV, FEandRDmethods), iterativemethods andmultigrid, solutionadaptivemeshtechniques, errorestimationandc- trol, parallelalgorithms. -Innovativemodelingof?owphysicsintheareaofcompressibleandinc- pressible ?ows: hypersonic and reacting ?ows, two-phase ?ows, turbulence (LES, DES, DNS, andtransition), vortexdynamics, boundarylayerstability, multi-scalephysics, magnetohydrodynamics. Preface VII -advancedapplicationsusingtheabovementionedinnovativetechnology, and multidisciplinaryapplicationsincludingaero-elasticityandaero-acoustics. ThanksareduetooursponsorsNASA, theFWOResearchFoundation FlandersandtheEuropeanUnionthroughtheEUA4XMarieCurieproject. Inparticular, thegenerousgrantfromNASAisakeyfactorinthesuccessof thisconferenceseriesandthepublicationoftheseProceedings. Wealsowouldliketothankthesta?andPhDstudentsofthevonKarman InstituteandtheDepartmentof?ow, heatandcombustionmechanicsofthe University of Gent, for the help they provided toward the success of this conference. Sint-Genesius-Rode, Belgium HermanDeconinck vonKarmanInstituteforFluidDynamics Ghent, Belgium ErikDick GhentUniversity September2006 ConferenceChair Contents PartIInvitedSpeakers Twonewtechniquesforgeneratingexactlyincompressible approximatevelocities BernardoCockburn. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 RoleofHigh-EndComputinginMeetingNASA'sScience andEngineeringChallenges RupakBiswas, EugeneL. Tu, WilliamR. VanDalsem. . . . . . . . . . . . . . . . 14 RecentAdvancesofMulti-phaseFlowComputationwiththe AdaptiveSoroban-gridCubicInterpolatedPropagation(CIP) Method TakashiYabe, YouichiOgata, KenjiTakizawa. . . . . . . . . . . . . . . . . . . . . . . 29 PartIISchemes OntheComputationofSteady-StateCompressibleFlows UsingaDGMethod HongLuo, JosephD. Baum, RainaldL]ohner. . . . . . . . . . . . . . . . . . . . . . . . 47 Space-TimeDiscontinuousGalerkinMethodforLarge AmplitudeNonlinearWaterWaves YanXu, JaapJ. W. vanderVegt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 AdiscontinuousGalerkinmethodwi

Download or read book A Time Accurate Upwind Unstructured Finite Volume Method for Compressible Flow with Cure of Pathological Behaviors written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2019-01-13 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A time-accurate, upwind, finite volume method for computing compressible flows on unstructured grids is presented. The method is second order accurate in space and time and yields high resolution in the presence of discontinuities. For efficiency, the Roe approximate Riemann solver with an entropy correction is employed. In the basic Euler/Navier-Stokes scheme, many concepts of high order upwind schemes are adopted: the surface flux integrals are carefully treated, a Cauchy-Kowalewski time-stepping scheme is used in the time-marching stage, and a multidimensional limiter is applied in the reconstruction stage. However even with these up-to-date improvements, the basic upwind scheme is still plagued by the so-called "pathological behaviors," e.g., the carbuncle phenomenon, the expansion shock, etc. A solution to these limitations is presented which uses a very simple dissipation model while still preserving second order accuracy. This scheme is referred to as the enhanced time-accurate upwind (ETAU) scheme in this paper. The unstructured grid capability renders flexibility for use in complex geometry; and the present ETAU Euler/Navier-Stokes scheme is capable of handling a broad spectrum of flow regimes from high supersonic to subsonic at very low Mach number, appropriate for both CFD (computational fluid dynamics) and CAA (computational aeroacoustics). Numerous examples are included to demonstrate the robustness of the methods. Loh, Ching Y. and Jorgenson, Philip C. E. Glenn Research Center NAS3-0372; WBS 561581.02.08.03.18.02

Download or read book Efficient Implementation of High Order Accurate Numerical Methods on Unstructured Grids written by Wanai Li and published by Springer. This book was released on 2014-05-23 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the development of high-order finite volume methods and discontinuous Galerkin methods, and presents possible solutions to a number of important and common problems encountered in high-order methods, such as the shock-capturing strategy and curved boundary treatment, then applies these methods to solve compressible flows.

Download or read book Magnetohydrodynamic Modeling of the Solar Corona and Heliosphere written by Xueshang Feng and published by Springer. This book was released on 2019-08-01 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book covers intimately all the topics necessary for the development of a robust magnetohydrodynamic (MHD) code within the framework of the cell-centered finite volume method (FVM) and its applications in space weather study. First, it presents a brief review of existing MHD models in studying solar corona and the heliosphere. Then it introduces the cell-centered FVM in three-dimensional computational domain. Finally, the book presents some applications of FVM to the MHD codes on spherical coordinates in various research fields of space weather, focusing on the development of the 3D Solar-InterPlanetary space-time Conservation Element and Solution Element (SIP-CESE) MHD model and its applications to space weather studies in various aspects. The book is written for senior undergraduates, graduate students, lecturers, engineers and researchers in solar-terrestrial physics, space weather theory, modeling, and prediction, computational fluid dynamics, and MHD simulations. It helps readers to fully understand and implement a robust and versatile MHD code based on the cell-centered FVM.

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.

Download or read book Computational Aerodynamics on Unstructed Meshes written by Yun Zheng and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New 2D and 3D unstructured-grid based flow solvers have been developed for simulating steady compressible flows for aerodynamic applications. The codes employ the full compressible Euler/Navier-Stokes equations. The Spalart-Al Imaras one equation turbulence model is used to model turbulence effects of flows. The spatial discretisation has been obtained using a cell-centred finite volume scheme on unstructured-grids, consisting of triangles in 2D and of tetrahedral and prismatic elements in 3D. The temporal discretisation has been obtained with an explicit multistage Runge-Kutta scheme. An "inflation" mesh generation technique is introduced to effectively reduce the difficulty in generating highly stretched 2D/3D viscous grids in regions near solid surfaces. The explicit flow method is accelerated by the use of a multigrid method with consideration of the high grid aspect ratio in viscous flow simulations. A solution mesh adaptation technique is incorporated to improve the overall accuracy of the 2D inviscid and viscous flow solutions. The 3D flow solvers are parallelised in a MIMD fashion aimed at a PC cluster system to reduce the computing time for aerodynamic applications. The numerical methods are first applied to several 2D inviscid flow cases, including subsonic flow in a bump channel, transonic flow around a NACA0012 airfoil and transonic flow around the RAE 2822 airfoil to validate the numerical algorithms. The rest of the 2D case studies concentrate on viscous flow simulations including laminar/turbulent flow over a flat plate, transonic turbulent flow over the RAE 2822 airfoil, and low speed turbulent flows in a turbine cascade with massive separations. The results are compared to experimental data to assess the accuracy of the method. The over resolved problem with mesh adaptation on viscous flow simulations is addressed with a two phase mesh reconstruction procedure. The solution convergence rate with the aspect ratio adaptive multigrid method and the direct connectivity based multigrid is assessed in several viscous turbulent flow simulations. Several 3D test cases are presented to validate the numerical algorithms for solving Euler/Navier-Stokes equations. Inviscid flow around the M6 wing airfoil is simulated on the tetrahedron based 3D flow solver with an upwind scheme and spatial second order finite volume method. The efficiency of the multigrid for inviscid flow simulations is examined. The efficiency of the parallelised 3D flow solver and the PC cluster system is assessed with simulations of the same case with different partitioning schemes. The present parallelised 3D flow solvers on the PC cluster system show satisfactory parallel computing performance. Turbulent flows over a flat plate are simulated with the tetrahedron based and prismatic based flow solver to validate the viscous term treatment. Next, simulation of turbulent flow over the M6 wing is carried out with the parallelised 3D flow solvers to demonstrate the overall accuracy of the algorithms and the efficiency of the multigrid method. The results show very good agreement with experimental data. A highly stretched and well-formed computational grid near the solid wall and wake regions is generated with the "inflation" method. The aspect ratio adaptive multigrid displayed a good acceleration rate. Finally, low speed flow around the NREL Phase 11 Wind turbine is simulated and the results are compared to the experimental data.

Download or read book Mathematical and Computational Methods for Compressible Flow written by Miloslav Feistauer and published by Oxford University Press, USA. This book was released on 2003 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is concerned with mathematical and numerical methods for compressible flow. It aims to provide the reader with a sufficiently detailed and extensive, mathematically precise, but comprehensible guide, through a wide spectrum of mathematical and computational methods used in Computational Fluid Dynamics (CFD) for the numerical simulation of compressible flow. Up-to-date techniques applied in the numerical solution of inviscid as well as viscous compressible flow on unstructured meshes are explained, thus allowing the simulation of complex three-dimensional technically relevant problems. Among some of the methods addressed are finite volume methods using approximate Riemann solvers, finite element techniques, such as the streamline diffusion and the discontinuous Galerkin methods, and combined finite volume - finite element schemes. The book gives a complex insight into the numerics of compressible flow, covering the development of numerical schemes and their theoretical mathematical analysis, their verification on test problems and use in solving practical engineering problems. The book will be helpful to specialists coming into contact with CFD - pure and applied mathematicians, aerodynamists, engineers, physicists and natural scientists. It will also be suitable for advanced undergraduate, graduate and postgraduate students of mathematics and technical sciences.

Download or read book Towards an Efficient and Robust High Order Accurate Flow Solver for Viscous Compressible Flows written by Sachin Premasuthan and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the advance in CFD over the past few decades, the field of high-order methods for unstructured grids has not yet reached the level of maturity required to solve real flow problems on complicated geometries. The present thesis work makes an effort towards the realization of a flow solver that is high-order accurate but also efficient, robust and geometrically flexible at the same time. The approach to high-order spatial discretization is based on the Spectral Difference (SD) method for unstructured quadrilateral meshes. High-order (quadratic and cubic) representation is used for curved boundary surfaces. Due to their slow convergence rates with standard explicit time-stepping schemes, the use of high order schemes becomes viable only when there is some kind of convergence acceleration technique used. Towards this end, the multi-order (p-multigrid) method and Implicit time-stepping are implemented, and significant convergence acceleration is achieved for both steady and unsteady flow problems. Another significant challenge with using high-order methods is their inability to handle flow discontinuities. An artificial viscosity based approach is designed and implemented to enable computation of flows with shocks. Adaptive mesh and order refinement have great potential in reducing the computational effort required to reach a specified level of accuracy, particularly in the context of high-order formulations. The capability for adaptive mesh and order refinement is enabled using mortar elements to handle non-conforming solution approximations at the cell interfaces. The flow solver is tested, validated and applied to a variety of flow problems. The current work also demonstrates the effectiveness of computational tools such as convergence acceleration, shock-capturing and adaptive refinement, for enhancing the efficiency and robustness of high order flow computations.

Download or read book Fluid Mechanics and Fluid Power Vol 3 written by Suvanjan Bhattacharyya and published by Springer Nature. This book was released on 2023-04-17 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the select proceedings of the 48th National Conference on Fluid Mechanics and Fluid Power (FMFP 2021) held at BITS Pilani in December 2021. It covers the topics such as fluid mechanics, measurement techniques in fluid flows, computational fluid dynamics, instability, transition and turbulence, fluid‐structure interaction, multiphase flows, micro- and nanoscale transport, bio-fluid mechanics, aerodynamics, turbomachinery, propulsion and power. The book will be useful for researchers and professionals interested in the broad field of mechanics.

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 The Finite Volume Method in Computational Fluid Dynamics written by F. Moukalled and published by Springer. This book was released on 2015-08-13 with total page 799 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook explores both the theoretical foundation of the Finite Volume Method (FVM) and its applications in Computational Fluid Dynamics (CFD). Readers will discover a thorough explanation of the FVM numerics and algorithms used for the simulation of incompressible and compressible fluid flows, along with a detailed examination of the components needed for the development of a collocated unstructured pressure-based CFD solver. Two particular CFD codes are explored. The first is uFVM, a three-dimensional unstructured pressure-based finite volume academic CFD code, implemented within Matlab. The second is OpenFOAM®, an open source framework used in the development of a range of CFD programs for the simulation of industrial scale flow problems. With over 220 figures, numerous examples and more than one hundred exercise on FVM numerics, programming, and applications, this textbook is suitable for use in an introductory course on the FVM, in an advanced course on numerics, and as a reference for CFD programmers and researchers.

Download or read book Frontiers of Computational Fluid Dynamics 1994 written by D. A. Caughey and published by . This book was released on 1994 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: Frontiers of Computational Fluid Dynamics 1994 Edited by D. A. Caughey Cornell University, Ithaca, New York, USA M. M. Hafez University of California, Davis, USA This book presents the current state of the art of Computational Fluid Dynamics (CFD). It is dedicated to Antony Jameson, in appreciation of his contributions to this field. Recent achievements in the various disciplines which contribute to CFD are discussed, including grid generation and adaptation, finite-volume and finite-element methods, multi-dimensional upwind schemes and multigrid convergence acceleration techniques. Simulations of inviscid and viscous flows are covered for both compressible and incompressible flows, with emphasis on flow control or optimal shape design in fluid mechanics. The book consists of 29 contributed chapters, which are grouped in six sections, covering: Design and Optimization of Aerodynamic Configurations Unstructured Grid Techniques Solution of the Euler Equations Solution of the Navier—Stokes Equations Applications in Aerodynamics Applications in Hydrodynamics Throughout the book, various approaches are critically examined, and new directions toward more efficient and robust tools of analysis and design, to meet the high expectations facing CFD, are emphasized.

Download or read book A High order Vertex based Central ENO Finite volume Scheme for Three dimensional Compressible Flows written by and published by . This book was released on 2015 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-order discretization methods offer the potential to reduce the computational cost associated with modeling compressible flows. However, it is difficult to obtain accurate high-order discretizations of conservation laws that do not produce spurious oscillations near discontinuities, especially on multi-dimensional unstructured meshes. A novel, high-order, central essentially non-oscillatory (CENO) finite-volume method that does not have these difficulties is proposed for tetrahedral meshes. The proposed unstructured method is vertex-based, which differs from existing cell-based CENO formulations, and uses a hybrid reconstruction procedure that switches between two different solution representations. It applies a high-order k-exact reconstruction in smooth regions and a limited linear reconstruction when discontinuities are encountered. Both reconstructions use a single, central stencil for all variables, making the application of CENO to arbitrary unstructured meshes relatively straightforward. The new approach was applied to the conservation equations governing compressible flows and assessed in terms of accuracy and computational cost. For all problems considered, which included various function reconstructions and idealized flows, CENO demonstrated excellent reliability and robustness. Up to fifth-order accuracy was achieved in smooth regions and essentially non-oscillatory solutions were obtained near discontinuities. The high-order schemes were also more computationally efficient for high-accuracy solutions, i.e., they took less wall time than the lower-order schemes to achieve a desired level of error. In one particular case, it took a factor of 24 less wall-time to obtain a given level of error with the fourth-order CENO scheme than to obtain the same error with the second-order scheme.

Download or read book Computational Fluid Dynamics 2010 written by Alexander Kuzmin and published by Springer Science & Business Media. This book was released on 2011-05-03 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Conference on Computational Fluid Dynamics is held every two years and brings together physicists, mathematicians and engineers to review and share recent advances in mathematical and computational techniques for modeling fluid flow. The proceedings of the 2010 conference (ICCFD6) held in St Petersburg, Russia, contain a selection of refereed contributions and are meant to serve as a source of reference for all those interested in the state of the art in computational fluid dynamics.

Download or read book A mixed spectral and finite volume method for compressible viscous flows written by Tommy Minyard and published by . This book was released on 1993 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Efficient Semi implicit Pressure based Scheme Employing a High resolution Finite Element Method for Simulating Transient and Steady Inviscid and Viscous Compressible Flows on Unstructured Grids written by Richard C. Martineau and published by . This book was released on 2002 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: