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Case studies in aerostructural wing planform and section optimization. AIAA paper 20045372, 22 nd Applied Aerodynamics Conference and Exhibit
"... This paper focuses on aerostructural optimization of wing for long range transport aircraft, using Adjoint based optimization. The paper explores and compares attainable limit such as attainable L/D vs. Mach number, which may be appreciable higher than the historical trend typically used in concept ..."
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Cited by 6 (2 self)
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This paper focuses on aerostructural optimization of wing for long range transport aircraft, using Adjoint based optimization. The paper explores and compares attainable limit such as attainable L/D vs. Mach number, which may be appreciable higher than the historical trend typically used in conceptual design. It also seeks to identify a discernable trend in the planform variables such as sweep, thicknesstochord ratio, aspect ratio, and chords for optimum wings. Results form wingfuselage and completeaircraftconfiguration optimizations indicate that by stretching the span together with decreasing sweep and thickening the wing sections the lifttodrag ratio can be increased without any penalty on the structure weight. I.
Efficient aerodynamic shape optimization
 AIAA Paper
, 2004
"... Since the present author first became involved in computational fluid dynamics, around 1970, the landscape has changed dramatically. At that time, panel methods had just come into use, and the world’s fastest super computer, the Control data 6600, had only 131000 words of memory (about 1 megabyte). ..."
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Cited by 5 (4 self)
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Since the present author first became involved in computational fluid dynamics, around 1970, the landscape has changed dramatically. At that time, panel methods had just come into use, and the world’s fastest super computer, the Control data 6600, had only 131000 words of memory (about 1 megabyte). Prior to the breakthrough of Murman and Cole [1970], no viable algorithms for computing transonic flow with shock
Aerostructural wing planform optimization
 Proceedings of the 42 st Aerospace Sciences Meeting & Exhibit
, 2004
"... This paper describes the formulation of optimization techniques based on control theory for wing section and planform design in viscous compressible flow modeled by the Reynolds Averaged NavierStokes equations. Because the two disciplines that are relevant to this problem are aerodynamics and struc ..."
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Cited by 5 (3 self)
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This paper describes the formulation of optimization techniques based on control theory for wing section and planform design in viscous compressible flow modeled by the Reynolds Averaged NavierStokes equations. Because the two disciplines that are relevant to this problem are aerodynamics and structures, an extension of a single to a multiple objective cost function is considered. A realistic model for the structural weight, which is sensitive to both planform variations and wing loading, is implemented. Results of optimizing a wingfuselage of a commercial transport aircraft show a successful tradeoff between the aerodynamic and structural cost functions, leading to meaningful wing planform designs. Results also indicate that large improvements in lifttodrag ratio can be achieved without any penalty on the structural weight by stretching the span along with decreasing the sweep angle, thickening the wingsections, and modifying the airfoil sections. Furthermore, by varying the weighting constants in the cost function, the “Pareto front ” can be captured, broadening the design range of optimal shapes. I.
A continuous adjoint method for unstructured grids
 16th AIAA Computational Fluid Dynamic Conference
, 2008
"... Adjointbased shape optimization methods have proven to be computationally efficient for aerodynamic problems. The majority of the studies on adjoint methods have used structured grids to discretize the computational domain. Because of the potential advantages of unstructured grids for complex confi ..."
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Cited by 5 (2 self)
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Adjointbased shape optimization methods have proven to be computationally efficient for aerodynamic problems. The majority of the studies on adjoint methods have used structured grids to discretize the computational domain. Because of the potential advantages of unstructured grids for complex configurations, in this study we have developed and validated a continuous adjoint formulation for unstructured grids. The hurdles posed in the computation of the gradient for unstructured grids are resolved by using a reduced gradient formulation. The methods to impose thickness constraints on unstructured grids are also discussed. The results for two and threedimensional simulations of airfoils and wings in inviscid transonic flow are used to validate the design procedure. Finally, the design procedure is applied to redesign the shape of a transonic business jet configuration; we were able to reduce the inviscid drag of the aircraft from 235 to 216 counts resulting in a shockfree wing. Although the Euler equations are the focus of the study in this paper of the adjointbased approach, the solution of the adjoint system and gradient formulation can be conceptually extended to viscous flows. The approach presented in this study has been successfully used by the first and third authors for viscous flows using structured grids. However, particular aspects of the design process, such as the robustness of the mesh deformation process for unstructured grids, need more attention for viscous flows and are therefore the subject of ongoing research. Nomenclature
A CADFree and a CADBased Geometry Control System for Aerodynamic Shape Optimization,” AIAA Paper 2005–0451
, 2005
"... The performance of an aerodynamic shape optimization routine is greatly dependent on its geometry control system. This system must accurately parameterize the initial geometry and generate a flexible set of design variables for the optimization cycle. It must also generate new instances of the geome ..."
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Cited by 3 (0 self)
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The performance of an aerodynamic shape optimization routine is greatly dependent on its geometry control system. This system must accurately parameterize the initial geometry and generate a flexible set of design variables for the optimization cycle. It must also generate new instances of the geometry based on the changes to the design variables dictated by the optimization routine. In response to changes in the geometry, it is also desirable to generate a new surface grid with the same topology as the original grid. This new surface grid can be used to perturb the associated volume grid. This paper presents two geometry control systems, a CADfree system, and a CATIA V5 CADbased system. The two systems provide practical tools for aerodynamic optimization. They also provide a basis for comparing CADfree and CADbased systems and understanding additional issues that need to be addressed in order to develop reliable optimization systems.
Multipoint Wing Planform Optimization via Control Theory
"... This paper focuses on wing optimization via control theory using a multipoint design method. Based on the design methodology previously developed for wing section and planform optimization at a specific flight condition, it searches for a single wing shape that performs well over a range of flight ..."
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This paper focuses on wing optimization via control theory using a multipoint design method. Based on the design methodology previously developed for wing section and planform optimization at a specific flight condition, it searches for a single wing shape that performs well over a range of flight conditions. A new cost function is defined as the weighted sum of cost functions from a range of important flight conditions. Results of multipoint optimization of a long range transport aircraft show that improvement at each flight condition is not as large as the result from singlepoint optimization at one of the design points. However improvement in performance measures such as drag divergence Mach number and the lifttodrag ratio over a range of Mach numbers is significantly greater. I.
Multipoint AeroStructural Optimization of Wings Including Planform Variations
"... This paper focuses on wing optimization via control theory using a multipoint design method. Based on the design methodology previously developed for wing section and planform optimization at a specific flight condition, it searches for a single wing shape that performs well over a range of flight ..."
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Cited by 2 (0 self)
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This paper focuses on wing optimization via control theory using a multipoint design method. Based on the design methodology previously developed for wing section and planform optimization at a specific flight condition, it searches for a single wing shape that performs well over a range of flight conditions. Our previous experience with multipoint design without a detailed FE structural model, showed improvements in performance measures such as drag divergence Mach number and the lifttodrag ratio over a range of Mach numbers. In the current work, the flow solution is modified to allow for shape deformation under load. We achieve this by coupling SYN107 to FEAP (Robert Taylor, University of California at Berkeley). The resulting aeroelastic simulation is then used to determine the optimal airfoil section and wing planform definition. In the multipoint design the actual shape will now be different at the different design points. With the coupled aerostructural analysis we hope to determine the best jig shape for the multipoint design. I.
Aerodynamic Shape and Planform Optimization of Wings Using a Viscous Reduced Adjoint Gradient Formula
"... in the calculation of the complete gradient is e#ectively independent of the number of design variables. In the control theory approach the necessary gradients are obtained via the solution of the adjoint equations of the governing equations of interest. The only cost involved is the calculation of ..."
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in the calculation of the complete gradient is e#ectively independent of the number of design variables. In the control theory approach the necessary gradients are obtained via the solution of the adjoint equations of the governing equations of interest. The only cost involved is the calculation of one flow solution and one adjoint solution whose complexity is similar to that of the flow solution. The present work builds on the foundation of control theory for systems governed by partial di#erential equations originally laid out by J.L. Lions and first used in transonic flow by Jameson. In fact, the method has even been successfully used for the aerodynamic design of complete aircraft configurations. Recently the authors have also included wing planform as design variables and have successfully designed a wing of the aircraft configuration which produces a specified lift with minimum drag, while meeting other criteria such as low structure weight, su#cient fuel volume, and st
Advances in Aerodynamic Shape Optimization
, 2004
"... Introduction The focus of CFD applications has shifted to aerodynamic design. This shift has been mainly motivated by the availability of high performance computing platforms and by the development of new and e#cient analysis and design algorithms. In particular automatic design procedures, which u ..."
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Introduction The focus of CFD applications has shifted to aerodynamic design. This shift has been mainly motivated by the availability of high performance computing platforms and by the development of new and e#cient analysis and design algorithms. In particular automatic design procedures, which use CFD combined with gradientbased optimization techniques, have had a significant impact on the design process by removing di#culties in the decision making process faced by the aerodynamicist. A fast way of calculating the accurate gradient information is essential since the gradient calculation can be the most time consuming portion of the design algorithm. The computational cost of gradient calculation can be dramatically reduced by the control theory approach since the computational expense incurred in the calculation of the complete gradient is e#ectively independent of the number of design variables. The foundation of control theory for systems governed by partial di#erential equat
Application of Evolutionary Algorithm on Aerodynamic Wing Optimisation
"... Abstract: Search for safety and high efficiency is the driving force in the aerospace industry. This paper reports on application of a relatively new and very promising evolutionary algorithm SOMA with the intent to answer the question on optimal wing geometry. We describe aerodynamic model of the w ..."
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Abstract: Search for safety and high efficiency is the driving force in the aerospace industry. This paper reports on application of a relatively new and very promising evolutionary algorithm SOMA with the intent to answer the question on optimal wing geometry. We describe aerodynamic model of the wing, the evolutionary optimisation process and results we obtained. In this contribution present a modern, high performance global optimisation algorithm applied on real engineering application resulting into a set of evolutionarydesigned wings which we developed in cooperation with a leading civil aircraft design bureau and manufacturer. Key–Words: Evolutionary algorithms, Aerodynamics, Optimisation 1