Download or read book A Hybrid Explicit implicit Second order TVD Method on Adaptive Unstructured Grids for Unsteady Compressible Flows written by Farhang Norouzi and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: " This work is devoted to the development of a hybrid, explicit-implicit, scheme for simulation of unsteady compressible flows with shock waves. The proposed scheme is of the second-order accuracy in space and time for both explicit and implicit modes, while satisfying the TVD (Total Variation Diminishing) property. The scheme is designed for simulation of the compressible flows with temporal stiffness. In this situation,the numerical time step of explicit schemes is severely limited by particular conditions in a relatively small part of the computational domain, while the rest of the domain admits much higher time steps. The hybrid scheme is designed to operate in its implicit mode in the small areas causing temporal stiffness, thus allowing to proceed with higher time steps and reduce the computational time. In this study, a new hybridization approach is suggested. On its basis, the hybrid scheme is first introduced for hyperbolic conservation laws in one dimension. In order to satisfy the TVD property and obtain monotone solutions in the presence ofdiscontinuities, TVD limiters are applied to both spatial and temporal reconstructions. The second-order accuracy in time for the implicit mode, which is the main distinction of the proposed hybrid scheme in comparison with the existing methods, is achieved through a reconstruction of the solution in time. To make the reconstruction TVD preserving, a novel time limiter is derived. The stability condition and the relation to the hybridization factor of the new scheme are obtained. Moreover, the relationship of the proposed scheme with another existing hybrid method is revealed and analyzed. A set of one-dimensional test problems is used to demonstrate the accuracy and efficiency of the new hybrid scheme as well as to show its advantagesin comparison with the existing hybrid schemes. For two-dimensional problems, the hybrid scheme is generalized for the Euler and Navier-Stokes equations on unstructured grids. Similar to one-dimensional problems, reconstructions in space and time are applied with the corresponding TVD limiters. The newly proposed time limiter of the hybrid scheme is further generalized for unstructured grids. The non-linear system of discretized equations is solved using the Lower-Upper-Symmetric-Gauss-Seidel (LU-SGS) approximate factorization method for unstructured grids. In order to eliminate the factorization and linearization errors, internal iterations are introduced at each time step. The lower and upper matrices in the LU-SGS scheme are formed via reordering of grid nodes at each time step. In addition, local transient grid adaptation is applied near solution peculiarities, such as shock waves and contact surfaces. Viscous terms of the Navier-Stokes equations are also approximated with the second order of accuracy both in space and time in both explicit and implicit modes. The new hybrid scheme is applied to a number of demonstrative problems chosen to represent typical classes of gasdynamic problems with specific source of stiffness. The numerical results demonstrate the ability of the proposed hybrid scheme to produce the same accuracy as the purely explicit scheme (the well-known MUSCLHancock scheme), while reducing the computational time." --

Download or read book A Hybrid Implicit explicit Method for the Les of Compressible Flows on Unstructured Grids written by Mohammad Shoeybi and published by . This book was released on 2010 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Unstructured Grid Generation and Adaptive Solution Technique for High Reynolds number Compressible Flows written by Gregory Allan Ashford and published by . This book was released on 1996 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Implicit Method for the Computation of Unsteady Flows on Unstructured Grids written by V. Venkatakrishnan and published by . This book was released on 1995 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA SP written by and published by . This book was released on 1990 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1987 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 1124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Implicit and P Multi Grid Algorithms for High Order Spectral Difference Method on Unstructured Grids written by and published by . This book was released on 2009 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of high-order methods (order of accuracy> 2nd order) on unstructured grids is widely viewed as a major pacing item in computational fluid dynamics (CFD). Efficient high-order methods capable of handling complex geometries are required to compute vortex dominated flows, and to perform large eddy simulation and direct numerical simulation with complex configurations, and to predict aeroacoustic noise generation and propagation. The primary objective of the present research is to develop implicit, multigrid and adaptive solution algorithms for a promising high-order method, the spectral difference (SD) method. Several major activities were carried out: 1. The development of a hp-adaptation capability to capture both discontinuous and smooth flow features with high efficiency; 2. Development of a accuracy-preserving limiter for discontinuity-capturing for the high-order SD Navier-Stokes solver; 3. Demonstration of the developed code for real world unsteady vortex-dominated flow problems.

Download or read book Aeronautical Engineering written by and published by . This book was released on 1990 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).

Download or read book An Implicit Unstructured Adaptive grid Approach for Compressible Flows with Moving Boundaries written by Biing-Horng Liou and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Science Abstracts written by and published by . This book was released on 1992 with total page 1228 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aeronautical Engineering A Cumulative Index to a Continuing Bibliography supplement 248 written by and published by . This book was released on 1990 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of Turbomachinery written by and published by . This book was released on with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mathematical Reviews written by and published by . This book was released on 2002 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Solution Adaptive Structured unstructured Grid Procedure for Unsteady Flows written by Sanjay R. Mathur and published by . This book was released on 1993 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: