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Using High Resolution Design Spaces For Aerodynamic Shape Optimization Under Uncertainty
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Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721036660 Total Pages :32 pages Book Rating :4.0/5 (366 download)
Book Synopsis Using High Resolution Design Spaces for Aerodynamic Shape Optimization Under Uncertainty by : National Aeronautics and Space Administration (NASA)
Download or read book Using High Resolution Design Spaces for Aerodynamic Shape Optimization Under Uncertainty written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-12 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper explains why high resolution design spaces encourage traditional airfoil optimization algorithms to generate noisy shape modifications, which lead to inaccurate linear predictions of aerodynamic coefficients and potential failure of descent methods. By using auxiliary drag constraints for a simultaneous drag reduction at all design points and the least shape distortion to achieve the targeted drag reduction, an improved algorithm generates relatively smooth optimal airfoils with no severe off-design performance degradation over a range of flight conditions, in high resolution design spaces parameterized by cubic B-spline functions. Simulation results using FUN2D in Euler flows are included to show the capability of the robust aerodynamic shape optimization method over a range of flight conditions.Li, Wu and Padula, SharonLangley Research CenterHIGH RESOLUTION; SHAPE OPTIMIZATION; VARIATIONAL PRINCIPLES; PARAMETER IDENTIFICATION; ROBUSTNESS (MATHEMATICS); COMPUTATIONAL FLUID DYNAMICS; AIRFOILS; AERODYNAMIC COEFFICIENTS; DRAG REDUCTION; FLIGHT CONDITIONS; EULER EQUATIONS OF MOTION; LIFT; MULTIDISCIPLINARY DESIGN OPTIMIZATION; ALGORITHMS
Book Synopsis Using High Resolution Design Spaces for Aerodynamic Shape Optimization Under Uncertainty by : Wu Li
Download or read book Using High Resolution Design Spaces for Aerodynamic Shape Optimization Under Uncertainty written by Wu Li and published by BiblioGov. This book was released on 2013-07 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper explains why high resolution design spaces encourage traditional airfoil optimization algorithms to generate noisy shape modifications, which lead to inaccurate linear predictions of aerodynamic coefficients and potential failure of descent methods. By using auxiliary drag constraints for a simultaneous drag reduction at all design points and the least shape distortion to achieve the targeted drag reduction, an improved algorithm generates relatively smooth optimal airfoils with no severe off-design performance degradation over a range of flight conditions, in high resolution design spaces parameterized by cubic B-spline functions. Simulation results using FUN2D in Euler flows are included to show the capability of the robust aerodynamic shape optimization method over a range of flight conditions.
Book Synopsis Simulation-driven Aerodynamic Design Using Variable-fidelity Models by : Leifur Leifsson
Download or read book Simulation-driven Aerodynamic Design Using Variable-fidelity Models written by Leifur Leifsson and published by World Scientific. This book was released on 2015-01-09 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computer simulations is a fundamental tool of the design process in many engineering disciplines including aerospace engineering. However, although high-fidelity numerical models are accurate, they can be computationally expensive with evaluation time for a single design as long as hours, days or even weeks. Simulation-driven design using conventional optimization techniques may be therefore prohibitive.This book explores the alternative: performing computationally efficient design using surrogate-based optimization, where the high-fidelity model is replaced by its computationally cheap but still reasonably accurate representation: a surrogate. The emphasis is on physics-based surrogates. Application-wise, the focus is on aerodynamics and the methods and techniques described in the book are demonstrated using aerodynamic shape optimization cases. Applications in other engineering fields are also demonstrated.State-of-the-art techniques and a depth of coverage never published before make this a unique and essential book for all researchers working in aerospace and other engineering areas and dealing with optimization, computationally expensive design problems, and simulation-driven design.
Book Synopsis Shape Optimization in Adaptive Search Spaces by : George Robert Anderson
Download or read book Shape Optimization in Adaptive Search Spaces written by George Robert Anderson and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Design space dimensionality is a persistent obstacle to high-fidelity aerodynamic shape optimization. The burden typically falls to the designer to select the shape design variables, which restricts the design space and impacts computational efficiency. In this work, I develop a system that automatically adapts the shape parameterization to efficiently solve the given design problem. Optimization begins with a small set of design variables, which is then progressively refined to enable the discovery of superior designs. The adaptation is goal-oriented and is driven by a novel refinement indicator that focuses shape control resolution on regions with the highest potential to improve the design. This indicator is computed from adjoint sensitivity information and a quasi-Newton Hessian approximation, which are both readily available in many design frameworks. To verify that the system can autonomously discover parameters sufficient to solve a problem, three inverse design problems are examined. For these cases, the procedure robustly converges to the continuous optimum from different starting points and with different refinement strategies. Several airfoil and wing shape optimization problems are then performed. The adaptive approach generally yields smoother design trajectories, at substantially lower cost than under fixed or uniformly-refined parameterizations. Finally, I consider the combinatorial problem of finding an optimal layout for an adaptive, trailing edge flap system. In fewer than 100 simulations, the adaptive procedure discovers a flap layout that outperforms naive layouts. I conclude with a discussion of the tremendous potential this approach offers for many other disciplines and design environments.
Book Synopsis Management and Minimisation of Uncertainties and Errors in Numerical Aerodynamics by : Bernhard Eisfeld
Download or read book Management and Minimisation of Uncertainties and Errors in Numerical Aerodynamics written by Bernhard Eisfeld and published by Springer Science & Business Media. This book was released on 2013-02-11 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reports results from the German research initiative MUNA (Management and Minimization of Errors and Uncertainties in Numerical Aerodynamics), which combined development activities of the German Aerospace Center (DLR), German universities and German aircraft industry. The main objective of this five year project was the development of methods and procedures aiming at reducing various types of uncertainties that are typical of numerical flow simulations. The activities were focused on methods for grid manipulation, techniques for increasing the simulation accuracy, sensors for turbulence modelling, methods for handling uncertainties of the geometry and grid deformation as well as stochastic methods for quantifying aleatoric uncertainties.
Book Synopsis Advances in Evolutionary and Deterministic Methods for Design, Optimization and Control in Engineering and Sciences by : Edmondo Minisci
Download or read book Advances in Evolutionary and Deterministic Methods for Design, Optimization and Control in Engineering and Sciences written by Edmondo Minisci and published by Springer. This book was released on 2018-07-02 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents up-to-date material on the state of the art in evolutionary and deterministic methods for design, optimization and control with applications to industrial and societal problems from Europe, Asia, and America. EUROGEN 2015 was the 11th of a series of International Conferences devoted to bringing together specialists from universities, research institutions and industries developing or applying evolutionary and deterministic methods in design optimization, with emphasis on solving industrial and societal problems. The conference was organised around a number of parallel symposia, regular sessions, and keynote lectures focused on surrogate-based optimization in aerodynamic design, adjoint methods for steady & unsteady optimization, multi-disciplinary design optimization, holistic optimization in marine design, game strategies combined with evolutionary computation, optimization under uncertainty, topology optimization, optimal planning, shape optimization, and production scheduling.
Book Synopsis Application of Surrogate-based Global Optimization to Aerodynamic Design by : Emiliano Iuliano
Download or read book Application of Surrogate-based Global Optimization to Aerodynamic Design written by Emiliano Iuliano and published by Springer. This book was released on 2015-10-05 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamic design, like many other engineering applications, is increasingly relying on computational power. The growing need for multi-disciplinarity and high fidelity in design optimization for industrial applications requires a huge number of repeated simulations in order to find an optimal design candidate. The main drawback is that each simulation can be computationally expensive – this becomes an even bigger issue when used within parametric studies, automated search or optimization loops, which typically may require thousands of analysis evaluations. The core issue of a design-optimization problem is the search process involved. However, when facing complex problems, the high-dimensionality of the design space and the high-multi-modality of the target functions cannot be tackled with standard techniques. In recent years, global optimization using meta-models has been widely applied to design exploration in order to rapidly investigate the design space and find sub-optimal solutions. Indeed, surrogate and reduced-order models can provide a valuable alternative at a much lower computational cost. In this context, this volume offers advanced surrogate modeling applications and optimization techniques featuring reasonable computational resources. It also discusses basic theory concepts and their application to aerodynamic design cases. It is aimed at researchers and engineers who deal with complex aerodynamic design problems on a daily basis and employ expensive simulations to solve them.
Book Synopsis AIAA Journal by : American Institute of Aeronautics and Astronautics
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2006 with total page 1380 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerodynamic Shape Optimization of a Hsct Type Configuration with Improved Surface Definition by : National Aeronautics and Space Adm Nasa
Download or read book Aerodynamic Shape Optimization of a Hsct Type Configuration with Improved Surface Definition written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-22 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two distinct parametrization procedures of generating free-form surfaces to represent aerospace vehicles are presented. The first procedure is the representation using spline functions such as nonuniform rational b-splines (NURBS) and the second is a novel (geometrical) parametrization using solutions to a suitably chosen partial differential equation. The main idea is to develop a surface which is more versatile and can be used in an optimization process. Unstructured volume grid is generated by an advancing front algorithm and solutions obtained using an Euler solver. Grid sensitivity with respect to surface design parameters and aerodynamic sensitivity coefficients based on potential flow is obtained using an automatic differentiator precompiler software tool. Aerodynamic shape optimization of a complete aircraft with twenty four design variables is performed. High speed civil transport aircraft (HSCT) configurations are targeted to demonstrate the process. Thomas, Almuttil M. and Tiwari, Surendra N. Unspecified Center NCC1-68...
Book Synopsis Aircraft Aerodynamic Design by : András Sóbester
Download or read book Aircraft Aerodynamic Design written by András Sóbester and published by John Wiley & Sons. This book was released on 2014-09-23 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optimal aircraft design is impossible without a parametric representation of the geometry of the airframe. We need a mathematical model equipped with a set of controls, or design variables, which generates different candidate airframe shapes in response to changes in the values of these variables. This model's objectives are to be flexible and concise, and capable of yielding a wide range of shapes with a minimum number of design variables. Moreover, the process of converting these variables into aircraft geometries must be robust. Alas, flexibility, conciseness and robustness can seldom be achieved simultaneously. Aircraft Aerodynamic Design: Geometry and Optimization addresses this problem by navigating the subtle trade-offs between the competing objectives of geometry parameterization. It beginswith the fundamentals of geometry-centred aircraft design, followed by a review of the building blocks of computational geometries, the curve and surface formulations at the heart of aircraft geometry. The authors then cover a range of legacy formulations in the build-up towards a discussion of the most flexible shape models used in aerodynamic design (with a focus on lift generating surfaces). The book takes a practical approach and includes MATLAB®, Python and Rhinoceros® code, as well as ‘real-life’ example case studies. Key features: Covers effective geometry parameterization within the context of design optimization Demonstrates how geometry parameterization is an important element of modern aircraft design Includes code and case studies which enable the reader to apply each theoretical concept either as an aid to understanding or as a building block of their own geometry model Accompanied by a website hosting codes Aircraft Aerodynamic Design: Geometry and Optimization is a practical guide for researchers and practitioners in the aerospace industry, and a reference for graduate and undergraduate students in aircraft design and multidisciplinary design optimization.
Book Synopsis Investigation of Robust Optimization and Evidence Theory with Stochastic Expansions for Aerospace Applications Under Mixed Uncertainty by : Harsheel R. Shah
Download or read book Investigation of Robust Optimization and Evidence Theory with Stochastic Expansions for Aerospace Applications Under Mixed Uncertainty written by Harsheel R. Shah and published by . This book was released on 2015 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: "One of the primary objectives of this research is to develop a method to model and propagate mixed (aleatory and epistemic) uncertainty in aerospace simulations using DSTE. In order to avoid excessive computational cost associated with large scale applications and the evaluation of Dempster Shafer structures, stochastic expansions are implemented for efficient UQ. The mixed UQ with DSTE approach was demonstrated on an analytical example and high fidelity computational fluid dynamics (CFD) study of transonic flow over a RAE 2822 airfoil. Another objective is to devise a DSTE based performance assessment framework through the use of quantification of margins and uncertainties. Efficient uncertainty propagation in system design performance metrics and performance boundaries is achieved through the use of stochastic expansions. The technique is demonstrated on: (1) a model problem with non-linear analytical functions representing the outputs and performance boundaries of two coupled systems and (2) a multi-disciplinary analysis of a supersonic civil transport. Finally, the stochastic expansions are applied to aerodynamic shape optimization under uncertainty. A robust optimization algorithm is presented for computationally efficient airfoil design under mixed uncertainty using a multi-fidelity approach. This algorithm exploits stochastic expansions to create surrogate models utilized in the optimization process. To reduce the computational cost, output space mapping technique is implemented to replace the high-fidelity CFD model by a suitably corrected low-fidelity one. The proposed algorithm is demonstrated on the robust optimization of NACA 4-digit airfoils under mixed uncertainties in transonic flow"--Abstract, page iv.
Book Synopsis Conceptual Shape Optimization of Entry Vehicles by : Dominic Dirkx
Download or read book Conceptual Shape Optimization of Entry Vehicles written by Dominic Dirkx and published by Springer. This book was released on 2016-12-09 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the parameterization of entry capsules, including Apollo capsules and planetary probes, and winged entry vehicles such as the Space Shuttle and lifting bodies. The aerodynamic modelling is based on a variety of panel methods that take shadowing into account, and it has been validated with flight and wind tunnel data of Apollo and the Space Shuttle. The shape optimization is combined with constrained trajectory analysis, and the multi-objective approach provides the engineer with a Pareto front of optimal shapes. The method detailed in Conceptual Shape Optimization of Entry Vehicles is straightforward, and the output gives the engineer insight in the effect of shape variations on trajectory performance. All applied models and algorithms used are explained in detail, allowing for reconstructing the design tool to the researcher’s requirements. Conceptual Shape Optimization of Entry Vehicles will be of interest to both researchers and graduate students in the field of aerospace engineering, and to practitioners within the aerospace industry.
Download or read book Aerospace America written by and published by . This book was released on 2003 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerodynamic Gradient-based Optimization Using Computational Fluid Dynamics and Discrete Sensitivities for Practical Problems by : Mohagna Jayendrarai Pandya
Download or read book Aerodynamic Gradient-based Optimization Using Computational Fluid Dynamics and Discrete Sensitivities for Practical Problems written by Mohagna Jayendrarai Pandya and published by . This book was released on 1997 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Active Subspaces by : Paul G. Constantine
Download or read book Active Subspaces written by Paul G. Constantine and published by SIAM. This book was released on 2015-03-17 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scientists and engineers use computer simulations to study relationships between a model's input parameters and its outputs. However, thorough parameter studies are challenging, if not impossible, when the simulation is expensive and the model has several inputs. To enable studies in these instances, the engineer may attempt to reduce the dimension of the model's input parameter space. Active subspaces are an emerging set of dimension reduction tools that identify important directions in the parameter space. This book describes techniques for discovering a model's active subspace and proposes methods for exploiting the reduced dimension to enable otherwise infeasible parameter studies. Readers will find new ideas for dimension reduction, easy-to-implement algorithms, and several examples of active subspaces in action.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781725014596 Total Pages :34 pages Book Rating :4.0/5 (145 download)
Book Synopsis A Preconditioning Method for Shape Optimization Governed by the Euler Equations by : National Aeronautics and Space Administration (NASA)
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...
Book Synopsis Aerodynamics of Wind Turbines, 2nd edition by : Martin O. L. Hansen
Download or read book Aerodynamics of Wind Turbines, 2nd edition written by Martin O. L. Hansen and published by Routledge. This book was released on 2013-05-13 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The new material includes a description of the effects of the dynamics and how this can be modelled in an ?aeroelastic code?, which is widely used in the design and verification of modern wind turbines. Further, the description of how to calculate the vibration of the whole construction, as well as the time varying loads, has been substantially updated.
