Computational Fluid Dynamics: Principles and Applications, Third Edition presents students, engineers, and scientists with all they need to gain a solid understanding of the numerical methods and principles underlying modern computation techniques in fluid dynamics By providing complete coverage of the essential knowledge required in order to write codes or understand commercial codes, the book gives the reader an overview of fundamentals and solution strategies in the early chapters before moving on to cover the details of different solution techniques

	This updated edition includes new worked programming examples, expanded coverage and recent literature regarding incompressible flows, the Discontinuous Galerkin Method, the Lattice Boltzmann Method, higher-order spatial schemes, implicit Runge-Kutta methods and parallelization

	An accompanying companion website contains the sources of 1-D and 2-D Euler and Navier-Stokes flow solvers (structured and unstructured) and grid generators, along with tools for Von Neumann stability analysis of 1-D model equations and examples of various parallelization techniques



	
		Will provide you with the knowledge required to develop and understand modern flow simulation codes
	
		Features new worked programming examples and expanded coverage of incompressible flows, implicit Runge-Kutta methods and code parallelization, among other topics
	
		Includes accompanying companion website that contains the sources of 1-D and 2-D flow solvers as well as grid generators and examples of parallelization techniques

Computational Fluid Dynamics: Principles and Applications Ed. 3

Developers of computer codes, analysts who use the codes, and decision makers who rely on the results of the analyses face a critical question: How should confidence in modeling and simulation be critically assessed? Verification and validation (V&V) of computational simulations are the primary methods for building and quantifying this confidence. Briefly, verification is the assessment of the accuracy of the solution to a computational model. Validation is the assessment of the accuracy of a computational simulation by comparison with experimental data. In verification, the relationship of the simulation to the real world is not an issue. In validation, the relationship between computation and the real world, i.e., experimental data, is the issue.

/pdf/verification-validation-and-predictive-capability-in-ru25qjss9j.pdf

Verification, Validation, and Predictive Capability in Computational Engineering and Physics

Anisotropic grid adaptation for functional outputs: application to two-dimensional viscous flows

http://www-personal.umich.edu/~kfid/pubs/Fidkowski_Oliver_Lu_Darmofal_2005.pdf

p-Multigrid solution of high-order discontinuous Galerkin discretizations of the compressible Navier-Stokes equations

A method is presented for generating three-dimensional viscous unstructured grids on complex configurations. The approach stems from a natural extension of the advancing-layers method (ALM) that has been successfully applied to two-dimensional problems in prior work. High-aspect-ratio tetrahedral cells are constructed in viscous dominated flow regions by the ALM, with the remaining isotropic cells generated by the conventional advancing- front method. Relying on a totally unstructured grid-generation strategy, the method benefits from a high degree of flexibility and automation required for generating grids around complex geometries. Sample three-dimensional grids around complex configurations are presented to show the capability of the method. NSTRUCTURED grid methodology has demonstrated consid- erable success in computational fluid dynamics (CFD) mainly due to its inherent flexibility for discretization of geometrically com- plex domains. The growing number of new techniques and publi- cations imply the importance and increased interest in this class of grids. A thorough survey of the subject is given in Ref. 1. However, despite their remarkable effectiveness in computation of complex inviscid flow fields, unstructured grids have yet to provide for the routine computation of the Navier-Stokes equations in three dimen- sions. The lack of a robust unstructured grid strategy for generating highly stretched cells has been a major obstacle to applying such methodology to complex three-dimensional viscous-flow problems. Among the numerous references on the unstructured grid method- ology in the literature, there are only a few that discuss the problem of three-dimensi onal viscous flow on unstructured grids. Notable among the references that address unstructured viscous grid gener- ation are those cited in Refs. 2-10. Although most of the reported techniques have provided appropriate results for the specific applica- tions shown, many lack the desired generality, flexibility, efficiency, automation, and robustness. Semiunstructured techniques, for example, retain some of the limitations of structured grid-generation methods that impair the re- quired flexibility and robustness of the method to handle arbitrary three-dimensional complex configurations. Prismatic grids are ef- ficient in terms of computer memory requirement and are effec- tive as long as the configuration under consideration is relatively simple. For geometrically complex domains, this class of grid- generation techniques requires sophisticated schemes, to ensure the integrity of generated grids, which makes the method computation- ally intensive.3 Alternatively, prisms have been coupled with more flexible grids (e.g., tetrahedral) to form hybrid grids.5 This type of grid requires a special flow solution strategy to treat different cell types in the field. Furthermore, to form a one-to-one connection between the prismatic and tetrahedral cells, an identical number of prism layers should be maintained globally to obscure the quadri- lateral faces of prisms that obviously do not match with triangular faces of tetrahedral cells. This may limit the extent and flexibility of the prismatic portion of hybrid grids and, thus, reduce the capa- bility of the method for complex problems. Realistic configurations involving sharp edges, integrated components, gaps between close surfaces, etc., are examples of such complexities that require extra careful attention and enhanced capabilities that the existing semi- unstructured techniques may lack.

Three-dimensional unstructured viscous grids by the advancing-layers method

The NASA Tetrahedral Unstructured Software System (TetrUSS) was developed during the 1990's to provide a rapid aerodynamic analysis and design capability to applied aerodynamicists. The system is comprised of loosely integrated, user-friendly software that enables the application of advanced Euler and Navier-Stokes tetrahedral finite volume technology to complex aerodynamic problems. TetrUSS has matured well because of the generous feedback from many willing users representing a broad cross-section of background and skill levels. This paper presents an overview of the current capabilities of the TetrUSS system along with some representative results from selected applications.

/pdf/the-nasa-tetrahedral-unstructured-software-system-tetruss-ueyr535t4b.pdf

The NASA Tetrahedral Unstructured Software System (TETRUSS)

The results from the first AIAA CFD Drag Prediction Workshop are summarized. The workshop was designed specifically to assess the state-of-the-art of computational fluid dynamics methods for force and moment prediction. An impartial forum was provided to evaluate the effectiveness of existing computer codes and modeling techniques, and to identify areas needing additional research and development. The subject of the study was the DLR-F4 wing-body configuration, which is representative of transport aircraft designed for transonic flight. Specific test cases were required so that valid comparisons could be made. Optional test cases included constant-C(sub L) drag-rise predictions typically used in airplane design by industry. Results are compared to experimental data from three wind tunnel tests. A total of 18 international participants using 14 different codes submitted data to the workshop. No particular grid type or turbulence model was more accurate, when compared to each other, or to wind tunnel data. Most of the results overpredicted C(sub Lo) and C(sub Do), but induced drag (dC(sub D)/dC(sub L)(exp 2)) agreed fairly well. Drag rise at high Mach number was underpredicted, however, especially at high C(sub L). On average, the drag data were fairly accurate, but the scatter was greater than desired. The results show that well-validated Reynolds-Averaged Navier-Stokes CFD methods are sufficiently accurate to make design decisions based on predicted drag.

/pdf/summary-of-data-from-the-first-aiaa-cfd-drag-prediction-43ep13kd51.pdf

Summary of Data from the First AIAA CFD Drag Prediction Workshop

A complete ``geometry to drag-polar'''' analysis capability for the three-dimensional high-lift configurations is described. The approach is based on the use of unstructured meshes in order to enable rapid turnaround for complicated geometries that arise in high-lift configurations. Special attention is devoted to creating a capability for enabling analyses on highly resolved grids. Unstructured meshes of several million vertices are initially generated on a work-station, and subsequently refined on a supercomputer. The flow is solved on these refined meshes on large parallel computers using an unstructured agglomeration multigrid algorithm. Good prediction of lift and drag throughout the range of incidences is demonstrated on a transport take-off configuration using up to 24.7 million grid points. The feasibility of using this approach in a production environment on existing parallel machines is demonstrated, as well as the scalability of the solver on machines using up to 1450 processors.

/pdf/large-scale-parallel-unstructured-mesh-computations-for-3d-2c36gtbglg.pdf

Large-scale parallel unstructured mesh computations for 3D high-lift analysis

A new approach for distribution of grid points on the surface and in the volume has been developed. In addition to the point and line sources of prior work, the new approach utilizes surface and volume sources for automatic curvature-based grid sizing and convenient point distribution in the volume. A new exponential growth function produces smoother and more efficient grids and provides superior control over distribution of grid points in the field. All types of sources support anisotropic grid stretching which not only improves the grid economy but also provides more accurate solutions for certain aerodynamic applications. The new approach does not require a three-dimensional background grid as in the previous methods. Instead, it makes use of an efficient bounding-box auxiliary medium for storing grid parameters defined by surface sources. The new approach is less memory-intensive and more efficient computationally. The grids generated with the new method either eliminate the need for adaptive grid refinement for certain class of problems or provide high quality initial grids that would enhance the performance of many adaptation methods.

Advanced Unstructured Grid Generation for Complex Aerodynamic Applications

Acompletegeometryto drag polaranalysiscapabilityforthree-dimensionalhigh-liftcone gurationsisdescribed. The approach is based on the use of unstructured meshes to enable rapid turnaround for complicated geometries that arise in high-lift cone gurations. Special attention is devoted to creating a capability for enabling analyses on highly resolved grids. Unstructured meshes of several million vertices are initially generated on a workstation and subsequently are ree ned on a supercomputer. The e ow is solved on these ree ned meshes on large parallel computers using an unstructured agglomeration multigrid algorithm. Good prediction of lift and drag throughout the range of incidences is demonstrated on a transport takeoff cone guration using up to 24 :7 £ 10 6 grid points. The feasibility of using this approach in a production environment on existing parallel machines is demonstrated, as well as the scalability of the solver on machines using up to 1450 processors.

Shahyar Z. Pirzadeh

Papers

The NASA Tetrahedral Unstructured Software System (TETRUSS)

Summary of Data from the First AIAA CFD Drag Prediction Workshop

Large-scale parallel unstructured mesh computations for 3D high-lift analysis

Advanced Unstructured Grid Generation for Complex Aerodynamic Applications

Large-Scale Parallel Unstructured Mesh Computations for Three-Dimensional High-Lift Analysis