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Aerodynamic Shape Optimization of Wings including Planform Variations
 AIAA paper 20030210, 41st Aerospace Sciences Meeting & Exhibit
, 2003
"... This paper describes the formulation of optimization techniques based on control theory for aerodynamic shape design in inviscid compressible flow modelled by the Euler equations. The design methodology has been extended to include wing planform optimization ..."
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Cited by 16 (14 self)
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This paper describes the formulation of optimization techniques based on control theory for aerodynamic shape design in inviscid compressible flow modelled by the Euler equations. The design methodology has been extended to include wing planform optimization
Using Response Surfaces and Expected Improvement to Optimize Snake Robot Gait Parameters
"... Abstract — Several categories of optimization problems suffer from expensive objective function evaluation, driving the need for smart selection of subsequent experiments. One such category of problems involves physical robotic systems, which often require significant time, effort, and monetary expe ..."
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Cited by 11 (2 self)
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Abstract — Several categories of optimization problems suffer from expensive objective function evaluation, driving the need for smart selection of subsequent experiments. One such category of problems involves physical robotic systems, which often require significant time, effort, and monetary expenditure in order to run tests. To assist in the selection of the next experiment, there has been a focus on the idea of response surfaces in recent years. These surfaces interpolate the existing data and provide a measure of confidence in their error, serving as a lowfidelity surrogate function that can be used to more intelligently choose the next experiment. In this paper, we robustly implement a previous algorithm based on the response surface methodology with an expected improvement criteria. We apply this technique to optimize openloop gait parameters for snake robots, and demonstrate improved locomotive capabilities. I.
Aerodynamic Design of Cascades by Using an Adjoint Equation Method," AIAA Paper 20031068, AIAA 41st Aerospace Sciences Meeting and Exhibit
 of 13 American Institute of Aeronautics and Astronautics Paper 20051006 6Wu
, 2003
"... A continuous adjoint equation method is developed for the aerodynamic design of cascade blades in a twodimensional, inviscid, and compressible
ow. A cost function based on a prescribed target pressure distribution is dened and the purpose of design is to minimize the value of the cost function. Th ..."
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Cited by 6 (5 self)
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A continuous adjoint equation method is developed for the aerodynamic design of cascade blades in a twodimensional, inviscid, and compressible
ow. A cost function based on a prescribed target pressure distribution is dened and the purpose of design is to minimize the value of the cost function. The adjoint equations and the corresponding boundary conditions are derived based on the Euler equations, the
ow boundary conditions, and the denition of the cost function. Gradient information is obtained by solving the adjoint equations. A onedimensional search algorithm is used to perform the optimization in the calculated gradient direction. Multigrid method is applied to accelerate the computation for both the Euler and the adjoint equations. Three transonic cascade blade design cases are tested. The results show that the method is eective and ecient for turbomachinery blade design. The eect of shape functions on the performance of the design method is discussed. I.
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.
Optimum Transonic Wing Design Using Control Theory
 IUTAM Symposium Transsonicum IV, Goettingen
, 2002
"... Introduction While aerodynamic prediction methods based CFD are now well established, and quite accurate and robust, the ultimate need in the design process is to find the optimum shape which maximizes the aerodynamic performance. One way to approach this objective is to view it as a control proble ..."
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Cited by 3 (3 self)
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Introduction While aerodynamic prediction methods based CFD are now well established, and quite accurate and robust, the ultimate need in the design process is to find the optimum shape which maximizes the aerodynamic performance. One way to approach this objective is to view it as a control problem, in which the wing is treated as a device which controls the flow to produce lift with minimum drag, while meeting other requirements such as low structure weight, sufficient fuel volume, and stability and control constrains. Here we apply the theory of optimal control of systems governed by partial differential equations with boundary control, in this case through changing the shape of the boundary. Using this theory, we can find the Frechet derivative (infinitely dimensional gradient) of the cost function with respect to the shape by solving an adjoint problem, and then we can make an improvement by making a modification in a descent direction. For example, the cost function might be the
Comparative Study of ThreeDimensional Wing Drag Minimization by Different Optimization Techniques
"... The main goal of this paper is to document a comparative study of different computationalfluiddynamicsbased optimization techniques applied to the solution of a threedimensional wing drag minimization problem. To achieve this objective, three optimization tools were used: SYN107 (Intelligent Aer ..."
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The main goal of this paper is to document a comparative study of different computationalfluiddynamicsbased optimization techniques applied to the solution of a threedimensional wing drag minimization problem. To achieve this objective, three optimization tools were used: SYN107 (Intelligent Aerodynamics International), MDOPT (The Boeing Company), and OPTIMAS (Israel Aerospace Industries). The first tool employs gradientbased search techniques using the continuous adjoint equation, the second one is a responsesurface method, and the last one uses a floatingpoint genetic algorithm as its search engine. As the starting geometry, the public domain DPWW1 wing (a test case for the Third AIAA Drag Prediction Workshop) was used. The comparisons included herein are provided in three stages: cross analysis of the initial geometry by the computational fluid dynamics tools employed in the optimizations, optimization of the initial geometry to minimum drag, and cross analysis of optimal shapes achieved by the optimization tools using all computational fluid dynamics tools employed. The cross analysis also includes results from an independent computational fluid dynamics method that was not used in any of the optimization efforts. These results help quantify the level of variation that is inherent in, and can be expected from, application of the current stateoftheart aerodynamic optimization methods. The present work may be regarded as a move toward the construction of reliable test cases for an aerodynamic shape optimization problem. Another goal of this collaborative investigation is to collect lessons learned from this pilot project to help develop a model for an
Transonic Airfoil Shape Optimization in Preliminary Design Environment
"... A modified profile optimization method using a smoothest shape modification strategy (POSSEM) is developed for airfoil shape optimization in a preliminary design environment. POSSEM is formulated to overcome two technical difficulties frequently encountered when conducting multipoint airfoil optimiz ..."
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A modified profile optimization method using a smoothest shape modification strategy (POSSEM) is developed for airfoil shape optimization in a preliminary design environment. POSSEM is formulated to overcome two technical difficulties frequently encountered when conducting multipoint airfoil optimization within a highresolution design space: the generation of undesirable optimal airfoil shapes due to high frequency components in the parametric geometry model and significant degradation in the offdesign performance. To demonstrate the usefulness of POSSEM in a preliminary design environment, a design competition was conducted with the objective of improving a fairly welldesigned baseline airfoil at four transonic flight conditions without incurring any offdesign performance degradation. Independently, two designs were generated from the inverse design tool CDISC, while a third design was generated from POSSEM using over 200 control points of a cubic Bspline curve representation of the airfoil as design variables for the shape optimization. Pros and cons of all the airfoil designs are documented along with indepth analyses of simulation results. The POSSEM design exhibits a fairly smooth curvature and no degradation in the offdesign performance. Moreover, it has the lowest average drag among the
AerodynamicStructural Design Studies of LowSweep Transonic Wings
, 2008
"... The work presented herein explores the possibility of extending some commonly accepted limits related to the general layout of an efficient transonic wing. Specifically, the MachSweepThickness relationships are revisited at a cursory level. Highfidelity aerodynamic and aerodynamicstructural opti ..."
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The work presented herein explores the possibility of extending some commonly accepted limits related to the general layout of an efficient transonic wing. Specifically, the MachSweepThickness relationships are revisited at a cursory level. Highfidelity aerodynamic and aerodynamicstructural optimizations are performed on a set of wings constructed by a parametric variation on wing sweep. These study wings are derived from a baseline wing representative of current aircraft design practices. Initial results show that it may be possible to significantly reduce wing sweep without incurring either aerodynamic or structural penalties, especially for M ≤ 0.8 aircraft designs. Although more work is required to better quantify the magnitude of the potential improvements possible. Nonetheless, with existing aerodynamic and aerodynamicstructural optimization software, the possibility of enhancing the current knowledge base of wing planform layout is now within grasp. Background The current generation of civilian transport aircraft are typically designed with a moderately high swept wing. However, the planform layout of these wings were substantially influenced by historical design charts developed decades ago. These design charts were derived and updated from windtunnel and flight data collected over the years; they include shifts due to technology levels, such as that introduced by supercritical airfoil sections.
Mathematical Models and Methods in Applied Sciences c © World Scientific Publishing Company OPTIMAL CONTROL AND SHAPE OPTIMIZATION OF AORTOCORONARIC BYPASS ANASTOMOSES
, 2003
"... Communicated by N.Bellomo In this paper we present a new approach in the study of AortoCoronaric bypass anastomoses configurations. The theory of optimal control based on adjoint formulation is applied in order to optimize the shape of the zone of the incoming branch of the bypass (the toe) into t ..."
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Communicated by N.Bellomo In this paper we present a new approach in the study of AortoCoronaric bypass anastomoses configurations. The theory of optimal control based on adjoint formulation is applied in order to optimize the shape of the zone of the incoming branch of the bypass (the toe) into the coronary. The aim is to provide design indications in the perspective of future development for prosthetic bypasses. With a reduced model based on Stokes equations and a vorticity functional in the down field zone of bypass, a Taylor like patch is found. A feedback procedure with NavierStokes fluid model is proposed based on the analysis of wall shear stress and its related indexes such as OSI.