Download or read book Aerodynamic Optimization of Internal and External Flows Using the Adjoint equation Method written by Hsiao-Yuan Wu and published by . This book was released on 2005 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Variational Method for Aerodynamic Optimization Using the Navier Stokes Equations written by and published by . This book was released on 1997 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book The Variational Method for Aerodynamic Optimization Using the Navier Stokes Equations written by Bambang Soemarwoto and published by . This book was released on 1997 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aerodynamic Shape Optimization of Complex Aircraft Configurations Via an Adjoint Formulation written by James Reuther and published by . This book was released on 1996 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "This work describes the implementation of optimization techniques based on control theory for complex aircraft configurations. Here control theory is employed to derive the adjoint differential equations, the solution of which allows for a drastic reduction in computational costs over previous design methods [13, 12, 43, 38]. In our earlier studies [19, 20, 22, 23, 39, 25, 40, 41, 42] it was shown that this method could be used to devise effective optimization procedures for airfoils, wings and wing-bodies subject to either analytic or arbitrary meshes. Design formulations for both potential flows and flows governed by the Euler equations have been demonstrated, showing that such methods can be devised for various governing equations [39, 25]. In our most recent works [40, 42] the method was extended to treat wing-body configurations with a large number of mesh points, verifying that significant computational savings can be gained for practical design problems. In this paper the method is extended for the Euler equations to treat complete aircraft configurations via a new multiblock implementation. New elements include a multiblock-multigrid flow solver, a multiblock-multigrid adjoint solver, and a multiblock mesh perturbation scheme. Two design examples are presented in which the new method is used for the wing redesign of a transonic business jet."

Download or read book Aerodynamic Design Optimization on Unstructured Grids with a Continuous Adjoint Formulation written by W. Kyle Anderson and published by . This book was released on 1997 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aerodynamic Shape Optimization Using Control Theory written by James John Reuther and published by . This book was released on 1996 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "Aerodynamic shape design has long persisted as a difficult scientific challenge due [sic] its highly nonlinear flow physics and daunting geometric complexity. However, with the emergence of Computational Fluid Dynamics (CFD) it has become possible to make accurate predictions of flows which are not dominated by viscous effects. It is thus worthwhile to explore the extension of CFD methods for flow analysis to the treatment of aerodynamic shape design. Two new aerodynamic shape design methods are developed which combine existing CFD technology, optimal control theory, and numerical optimization techniques. Flow analysis methods for the potential flow equation and the Euler equations form the basis of the two respective design methods. In each case, optimal control theory is used to derive the adjoint differential equations, the solution of which provides the necessary gradient information to a numerical optimization method much more efficiently then [sic] by conventional finite differencing. Each technique uses a quasi-Newton numerical optimization algorithm to drive an aerodynamic objective function toward a minimum. An analytic grid perturbation method is developed to modify body fitted meshes to accommodate shape changes during the design process. Both Hicks-Henne perturbation functions and B-spline control points are explored as suitable design variables. The new methods prove to be computationally efficient and robust, and can be used for practical airfoil design including geometric and aerodynamic constraints. Objective functions are chosen to allow both inverse design to a target pressure distribution and wave drag minimization. Several design cases are presented for each method illustrating its practicality and efficiency. These include non-lifting and lifting airfoils operating at both subsonic and transonic conditions."

Download or read book Optimization and Computational Fluid Dynamics written by Dominique Thévenin and published by Springer Science & Business Media. This book was released on 2008-01-08 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: The numerical optimization of practical applications has been an issue of major importance for the last 10 years. It allows us to explore reliable non-trivial configurations, differing widely from all known solutions. The purpose of this book is to introduce the state-of-the-art concerning this issue and many complementary applications are presented.

Download or read book Admitting the Inadmissible Adjoint Formulation for Incomplete Cost Functionals in Aerodynamic Optimization written by Eyal Arian and published by . This book was released on 1997 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Adjoint Method Augmented with Grid Sensitivities for Aerodynamic Optimization written by Chad Oldfield and published by . This book was released on 2006 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discrete adjoint equations for an aerodynamic optimizer are augmented to explicitly include the sensitivities of the grid perturbation. The Newton-Krylov optimizer is paired with grid perturbations via the elasticity method with incremental stiffening. The elasticity method is computationally expensive, but exceptionally robust---high quality grids are produced, even for large shape changes. For the gradient calculation, instead of encompassing grid sensitivities in finite differenced terms for the adjoint equations, they are treated explicitly. This results in additional adjoint equations that must be solved. This augmented adjoint method requires less computational time than a function evaluation, and retains its speed as dimensionality is increased. The accuracy of the augmented adjoint method is excellent, allowing the optimizer to converge more fully. A discussion of the trade-off between lengthy development time and increased performance indicates that the method would be particularly well-suited to complicated three-dimensional configurations.

Download or read book A Preconditioning Method for Shape Optimization Governed by the Euler Equations written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-09 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: We consider a classical aerodynamic shape optimization problem subject to the compressible Euler flow equations. The gradient of the cost functional with respect to the shape variables is derived with the adjoint method at the continuous level. The Hessian (second order derivative of the cost functional with respect to the shape variables) is approximated also at the continuous level, as first introduced by Arian and Ta'asan (1996). The approximation of the Hessian is used to approximate the Newton step which is essential to accelerate the numerical solution of the optimization problem. The design space is discretized in the maximum dimension, i.e., the location of each point on the intersection of the computational mesh with the airfoil is taken to be an independent design variable. We give numerical examples for 86 design variables in two different flow speeds and achieve an order of magnitude reduction in the cost functional at a computational effort of a full solution of the analysis partial differential equation (PDE). Arian, Eyal and Vatsa, Veer N. Langley Research Center NASA/CR-1998-206926, NAS 1.26:206926, ICASE-98-14 NAS1-19480; RTOP 505-90-52-01...

Download or read book Perspectives in Flow Control and Optimization written by Max D. Gunzburger and published by SIAM. This book was released on 2003-01-01 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces several approaches for solving flow control and optimization problems through the use of modern methods.

Download or read book Aerodynamic Design Optimization Using the Navier Stokes and Adjoint Equations written by Chun-Ho Sung 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 Perspectives in Flow Control and Optimization written by Max D. Gunzburger and published by SIAM. This book was released on 2003-01-01 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flow control and optimization has been an important part of experimental flow science throughout the last century. As research in computational fluid dynamics (CFD) matured, CFD codes were routinely used for the simulation of fluid flows. Subsequently, mathematicians and engineers began examining the use of CFD algorithms and codes for optimization and control problems for fluid flows. Perspectives in Flow Control and Optimization presents flow control and optimization as a subdiscipline of computational mathematics and computational engineering. It introduces the development and analysis of several approaches for solving flow control and optimization problems through the use of modern CFD and optimization methods. The author discusses many of the issues that arise in the practical implementation of algorithms for flow control and optimization, and provides the reader with a clear idea of what types of flow control and optimization problems can be solved, how to develop effective algorithms for solving such problems, and potential problems in implementing the algorithms. Audience: this book is written for both those new to the field of control and optimization as well as experienced practitioners, including engineers, applied mathematicians, and scientists interested in computational methods for flow control and optimization. Readers with a solid background in calculus and only slight familiarity with partial differential equations should find the book easy to understand. Knowledge of fluid mechanics, computational fluid dynamics, calculus of variations, control theory or optimization is beneficial, but is not essential, to comprehend the bulk of the presentation. Only Chapter 6 requires a substantially higher level of mathematical knowledge, most notably in the areas of functional analysis, numerical analysis, and partial differential equations.

Download or read book Advanced Computational Fluid and Aerodynamics written by Paul G. Tucker and published by Cambridge University Press. This book was released on 2016-03-15 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book outlines the computational fluid dynamics evolution and gives an overview of the methods available to the engineer.

Download or read book Advances in Numerical Simulation in Physics and Engineering written by Carlos Parés and published by Springer. This book was released on 2014-07-05 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is mainly addressed to young graduate students in engineering and natural sciences who start to face numerical simulation, either at a research level or in the field of industrial applications. The main subjects covered are: Biomechanics, Stochastic Calculus, Geophysical flow simulation and Shock-Capturing numerical methods for Hyperbolic Systems of Partial Differential Equations. The book can also be useful to researchers or even technicians working at an industrial environment, who are interested in the state-of-the-art numerical techniques in these fields. Moreover, it gives an overview of the research developed at the French and Spanish universities and in some European scientific institutions. This book can be also useful as a textbook at master courses in Mathematics, Physics or Engineering.

Download or read book Numerical and Physical Aspects of Aerodynamic Flows written by T. Cebeci and published by Springer Science & Business Media. This book was released on 2013-11-09 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains revised and edited forms of papers presented at the Symposium on Numerical and Physical Aspects of Aerodynamic Flows, held at the California State University from 19 to 21 January 1981. The Symposium was organized to bring together leading research workers in those aspects of aerodynamic flows represented by the five parts and to fulfill the following purposes : first, to allow the presentation of technical papers which provide a basis for research workers to assess the present status of the subject and to formulate priorities for the future; and second, to promote informal discussion and thereby to assist the communication and develop ment of novel concepts. The format ofthe content ofthe volume is similar to that ofthe Symposium and addresses, in separate parts: Numerical Fluid Dynamics, Interactive Steady Boundary Layers, Singularities in Unsteady Boundary Layers, Transonic Flows, and Experimental Fluid Dynamics. The motivation for most of the work described relates to the internal and extern al aerodynamics of aircraft and to the development and appraisal of design methods based on numerical solutions to conservation equations in differential forms, for corresponding components. The chapters concerned with numerical fluid dynamics can, perhaps, be interpreted in a more general context, but the emphasis on boundary-Iayer flows and the special consideration oftransonic flows reflects the interest in external flows and the recent advances which have allowed the calculation methods to encompass transonic regions.

Download or read book Computational Fluid Dynamics 2004 written by Clinton Groth and published by Springer Science & Business Media. This book was released on 2006-09-27 with total page 853 pages. Available in PDF, EPUB and Kindle. Book excerpt: Those interested in state of the art in computational fluid dynamics will find this publication a valuable source of reference. The contributions are drawn from The International Conference on Computational Fluid Dynamics (ICCFD) held in 2004. The conference is staged every two years and brings together physicists, mathematicians and engineers who review and share recent advances in mathematical and computational techniques for modeling fluid dynamics.