A Comparison Of Design Variables For Control Theory Based Airfoil Optimization
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Aerodynamic Shape Optimization Using Control Theory
Author | : James John Reuther |
Publisher | : |
Total Pages | : 500 |
Release | : 1996 |
Genre | : Aerodynamics |
ISBN | : |
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."
CEAS/AIAA/ICASE/NASA Langley International Forum on Aeroelasticity and Structural Dynamics 1999
Author | : |
Publisher | : |
Total Pages | : 460 |
Release | : 1999 |
Genre | : Aeroelasticity |
ISBN | : |
These proceedings represent a collection of the latest advances in aeroelasticity and structural dynamics from the world community. Research in the areas of unsteady aerodynamics and aeroelasticity, structural modeling and optimazation, active control and adaptive structures, landing dynamics, certification and qualification, and validation testing are highlighted in the collection of papers. The wide range of results will lead to advances in the prediction and control of the structural response of aircraft and spacecraft.
Numerical Methods for Fluid Dynamics V
Author | : K. W. Morton |
Publisher | : Oxford University Press |
Total Pages | : 650 |
Release | : 1995 |
Genre | : Mathematics |
ISBN | : 9780198514800 |
This book contains the proceedings of an international conference on Numerical Methods for Fluid Dynamics held at the University of Oxford in April 1995. It provides a summary of recent research on the computational aspects of fluid dynamics. It includes contributions from many distinguished mathematicians and engineers and, as always, the standard of papers is high. The main themes of the book are algorithms and algorithmic needs arising from applications, Navier-Stokes on flexible grids, and environmental computational fluid dynamics. Graduate students of numerical analysis will find the up-to-date coverage of research in this book very useful.
Control Theory Based Airfoil Design Using the Euler Equations
Author | : Antony Jameson |
Publisher | : |
Total Pages | : 24 |
Release | : 1994 |
Genre | : Control theory |
ISBN | : |
Abstract: "This paper describes the implementation of optimization techniques based on control theory for airfoil design. In our previous work [9, 10, 15] it was shown that control theory could be employed to devise effective optimization procedures for two-dimensional profiles by using the potential flow equation with either a conformal mapping or a general coordinate system. The goal of our present work is to extend the development to treat the Euler equations in two-dimensions by procedures that can readily be generalized to treat complex shapes in three-dimensions. Therefore, we have developed methods which can address airfoil design through either an analytic mapping or an arbitrary grid perturbation method applied to a finite volume discretization of the Euler equations. Here the control law serves to provide computationally inexpensive gradient information to a standard numerical optimization method. Results are presented for both the inverse problem and drag minimization problem."
CFD for Design and Optimization
Author | : Oktay Baysal |
Publisher | : |
Total Pages | : 108 |
Release | : 1995 |
Genre | : Technology & Engineering |
ISBN | : |
Presents papers from the November 1995 congress demonstrating the utilization of CFD in a design environment. Topics include pre- and post-optimization sensitivity analyses; discrete and variational sensitivity methods; stochastic and genetic algorithms; shape optimization; inverse methods; trade-of