The Variational Method for Aerodynamic Optimization Using the Navier-Stokes Equations

The Variational Method for Aerodynamic Optimization Using the Navier-Stokes Equations
Author:
Publisher:
Total Pages: 34
Release: 1997
Genre:
ISBN:

This report describes the formulation of an aerodynamic shape design methodology using a compressible viscous flow model based on the Reynolds Averaged Navier Stokes equations. The aerodynamic shape is described by a set of geometrical design variables. The design problem is formulated as an optimization problem stated in terms of an aerodynamic objective functional which has to be minimized. The design scheme employs a gradient based optimization algorithm in order to obtain the optimum values of the design variables. The gradient of the aerodynamic functional with respect to the design variables is computed by means of the variational method, which requires the solution of an adjoint problem. The formulation of the adjoint problem is described which leads to a set of adjoint equations and boundary conditions. Using the flow variables and the adjoint variables, an expression for the gradient has been constructed. Computational results are presented for an inverse problem of an airfoil. It will be shown that, starting from an initial geometry of the NACA 0012 airfoil, the target pressure distribution and geometry of a best fit of the RAE 2822 airfoil in a transonic flow condition has been reconstructed successfully.

Modern Aerodynamic Methods for Direct and Inverse Applications

Modern Aerodynamic Methods for Direct and Inverse Applications
Author: Wilson C. Chin
Publisher: John Wiley & Sons
Total Pages: 349
Release: 2019-03-21
Genre: Technology & Engineering
ISBN: 1119580862

A powerful new monograph from an aerodynamicist reviewing modern conventional aerodynamic approaches, this volume covers aspects of subsonic, transonic and supersonic flow, inverse problems, shear flow analysis, jet engine power addition, engine and airframe integration, and other areas, providing readers with the tools needed to evaluate their own ideas and to implement the newer methods suggested in this book. This new book, by a prolific fluid-dynamicist and mathematician who has published more than twenty research monographs, represents not just another contribution to aerodynamics, but a book that raises serious questions about traditionally accepted approaches and formulations, providing new methods that solve longstanding problems of importance to the industry. While both conventional and newer ideas are discussed, the presentations are readable and geared to advanced undergraduates with exposure to elementary differential equations and introductory aerodynamics principles. Readers are introduced to fundamental algorithms (with Fortran source code) for basic applications, such as subsonic lifting airfoils, transonic supercritical flows utilizing mixed differencing, models for inviscid shear flow aerodynamics, and so on. These are models they can extend to include newer effects developed in the second half of the book. Many of the newer methods have appeared over the years in various journals and are now presented with deeper perspective and integration. This book helps readers approach the literature more critically. Rather than simply understanding an approach, for instance, the powerful "type differencing" behind transonic analysis, or the rationale behind "conservative" formulations, or the use of Euler equation methods for shear flow analysis when they are unnecessary, the author guides and motivates the user to ask why and why not and what if. And often, more powerful methods can be developed using no more than simple mathematical manipulations. For example, Cauchy-Riemann conditions, which are powerful tools in subsonic airfoil theory, can be readily extended to handle compressible flows with shocks, rotational flows, and even three-dimensional wing flowfields, in a variety of applications, to produce powerful formulations that address very difficult problems. This breakthrough volume is certainly a "must have" on every engineer's bookshelf.

Inverse Problems in Engineering Mechanics

Inverse Problems in Engineering Mechanics
Author: Masataka Tanaka
Publisher: Elsevier
Total Pages: 635
Release: 1998-11-09
Genre: Technology & Engineering
ISBN: 008053516X

Inverse problems can be found in many topics of engineering mechanics. There are many successful applications in the fields of inverse problems (non-destructive testing and characterization of material properties by ultrasonic or X-ray techniques, thermography, etc.). Generally speaking, the inverse problems are concerned with the determination of the input and the characteristics of a mechanical system from some of the output from the system. Mathematically, such problems are ill-posed and have to be overcome through development of new computational schemes, regularization techniques, objective functionals, and experimental procedures.Seventy-two papers were presented at the International Symposium on Inverse Problems in Mechanics (ISIP '98) held in March of 1998 in Nagano, where recent developments in the inverse problems in engineering mechanics and related topics were discussed. The main themes were: mathematical and computational aspects of the inverse problems, parameter or system identification, shape determination, sensitivity analysis, optimization, material property characterization, ultrasonic non-destructive testing, elastodynamic inverse problems, thermal inverse problems, and other engineering applications.

Parallel Computational Fluid Dynamics 2000

Parallel Computational Fluid Dynamics 2000
Author: C.B. Jenssen
Publisher: Gulf Professional Publishing
Total Pages: 601
Release: 2001-04-27
Genre: Science
ISBN: 0080538401

Parallel CFD 2000, the Twelfth in an International series of meetings featuring computational fluid dynamics research on parallel computers, was held May 22-25, 2000 in Trondheim, Norway.Following the trend of the past conferences, areas such as numerical schemes and algorithms, tools and environments, load balancing, as well as interdisciplinary topics and various kinds of industrial applications were all well represented in the work presented. In addition, for the first time in the Parallel CFD conference series, the organizing committee chose to draw special attention to certain subject areas by organizing a number of special sessions.We feel the emphasis of the papers presented at the conference reflect the direction of the research within parallel CFD at the beginning of the new millennium. It seems to be a clear tendency towards increased industrial exploitation of parallel CFD. Several presentations also demonstrated how new insight is being achieved from complex simulations, and how powerful parallel computers now make it possible to use CFD within a broader interdisciplinary setting.Obviously, successful application of parallel CFD still rests on the underlying fundamental principles. Therefore, numerical algorithms, development tools, and parallelization techniques are still as important as when parallel CFD was in is infancy. Furthermore, the novel concepts of affordable parallel computing as well as metacomputing show that exciting developments are still taking place.As is often pointed out however, the real power of parallel CFD comes from the combination of all the disciplines involved: Physics, mathematics, and computer science. This is probably one of the principal reasons for the continued popularity of the Parallel CFD Conferences series, as well as the inspiration behind much of the excellent work carried out on the subject. We hope that the papers in this book, both on an individual basis and as a whole, will contribute to that inspiration. Further details of Parallel CFD'99, as well as other conferences in this series, are available at http://www.parcfd.org

Computational Aerodynamics

Computational Aerodynamics
Author: Antony Jameson
Publisher: Cambridge University Press
Total Pages: 632
Release: 2022-09-01
Genre: Technology & Engineering
ISBN: 1108950280

Computational aerodynamics is a relatively new field in engineering that investigates aircraft flow fields via the simulation of fluid motion and sophisticated numerical algorithms. This book provides an excellent reference to the subject for a wide audience, from graduate students to experienced researchers and professionals in the aerospace engineering field. Opening with the essential elements of computational aerodynamics, the relevant mathematical methods of fluid flow and numerical methods for partial differential equations are presented. Stability theory and shock capturing schemes, and vicious flow and time integration methods are then comprehensively outlined. The final chapters treat more advanced material, including energy stability for nonlinear problems, and higher order methods for unstructured and structured meshes. Presenting over 150 illustrations, including representative calculations on unstructured meshes in color. This book is a rich source of information that will be of interest and importance in this pioneering field.

Variational Methods in Shape Optimization Problems

Variational Methods in Shape Optimization Problems
Author: Dorin Bucur
Publisher: Springer Science & Business Media
Total Pages: 232
Release: 2005-07-01
Genre: Mathematics
ISBN: 9780817643591

Shape optimization problems are treated from the classical and modern perspectives Targets a broad audience of graduate students in pure and applied mathematics, as well as engineers requiring a solid mathematical basis for the solution of practical problems Requires only a standard knowledge in the calculus of variations, differential equations, and functional analysis Driven by several good examples and illustrations Poses some open questions.