• Title/Summary/Keyword: Aerodynamic design optimization

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A STUDY ON THE EFFICIENCY OF AERODYNAMIC DESIGN OPTIMIZATION IN DISTRIBUTED COMPUTING ENVIRONMENT (분산컴퓨팅 환경에서 공력 설계최적화의 효율성 연구)

  • Kim Y.J.;Jung H.J.;Kim T.S.;Son C.H.;Joh C.Y.
    • Journal of computational fluids engineering
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    • v.11 no.2 s.33
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    • pp.19-24
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    • 2006
  • A research to evaluate the efficiency of design optimization was carried out for aerodynamic design optimization problem in distributed computing environment. The aerodynamic analyses which take most of computational work during design optimization were divided into several jobs and allocated to associated PC clients through network. This is not a parallel process based on domain decomposition in a single analysis rather than a simultaneous distributed-analyses using network-distributed computers. GBOM(gradient-based optimization method), SAO(Sequential Approximate Optimization) and RSM(Response Surface Method) were implemented to perform design optimization of transonic airfoils and evaluate their efficiencies. dimensional minimization followed by direction search involved in the GBOM was found an obstacle against improving efficiency of the design process in the present distributed computing system. The SAO was found fairly suitable for the distributed computing environment even it has a handicap of local search. The RSM is apparently the most efficient algorithm in the present distributed computing environment, but additional trial and error works needed to enhance the reliability of the approximation model deteriorate its efficiency from the practical point of view.

AERODYNAMIC DESIGN OPTIMIZATION OF ROTOR AIRFOIL WITH MULTIPLE CONSTRAINTS (다중제약조건을 갖는 로터익형의 공력 최적 설계)

  • Lee, S.M.;Sa, J.H.;Jeon, S.E.;Kim, C.J.;Park, S.H.;Chung, K.H.
    • Journal of computational fluids engineering
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    • v.15 no.2
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    • pp.79-85
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    • 2010
  • Aerodynamic design optimization of rotor airfoil has been performed with advanced design method for improved aerodynamic characteristics of ONERA airfoils. A multiple response surface method is used to consider various requirements in rotor airfoil design. Shape functions for mean camber line are proposed to extend possible design domain. Numerical simulations are performed using KFLOW, a Navier-Stokes solver with shear stress transport turbulence model. The present design method provides favorable configurations for the high performance rotor airfoil. Resulting optimized airfoils give better aerodynamic performance than the baseline airfoils.

Parallel 3-D Aerodynamic Shape Optimization on Unstructured Meshes

  • Lee, Sang-Wook;Kwon, Oh-Joon
    • International Journal of Aeronautical and Space Sciences
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    • v.4 no.1
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    • pp.45-52
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    • 2003
  • A three-dimensional aerodynamic shape optimization technique in inviscid compressible flows is developed by using a parallel continuous adjoint formulation on unstructured meshes. A new surface mesh modification method is proposed to overcome difficulties related to patch-level remeshing for unstructured meshes, and the effect of design sections on aerodynamic shape optimization is examined. Applications are made to three-dimensional wave drag minimization problems including an ONERA M6 wing and the EGLIN wing-pylon-store configuration. The results show that the present method is robust and highly efficient for the shape optimization of aerodynamic configurations, independent of the number of design variables used.

AERODYNAMIC DESIGN OPTIMIZATION OF ROTOR AIRFOIL WITH MULTIPLE CONSTRAINTS (다중제약조건을 가진 로터익형의 공력 최적 설계)

  • Lee, S.M.;Sa, J.H.;Jeon, S.E.;Kim, C.J.;Park, S.H.;Chung, K.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.55-59
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    • 2010
  • Aerodynamic design optimization of rotor airfoil has been performed with advanced design method for improved aerodynamic characteristics of ONERA airfoils as a baseline. A multiple response surface method is used to consider various consider various constraints in rotor airfoil design. Airfoil surface and mean camber line are modified using various shape functions. Numerical simulations are performed using KFLOW, a Navier-Stokes solver with shear stress transport turbulence model. The present design method provides favorable configurations for the high performance rotor airfoil. Resulting optimized air foils give better aerodynamic performance than the baseline airfoils.

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Aerodynamic Optimization Design for All Condition of Centrifugal Compressor

  • Lin, Zhirong;Gao, Xue-Lin;Yuan, Xin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.213-217
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    • 2008
  • This paper describes an application of centrifugal compressor optimization system, in which the blade profile of impeller is represented with NURBS(Non-Uniform Rational B-Spline) curve. A commercial CFD(Computational Fluid Dynamics) program named NUMECA fine/turbo was used to evaluate the performance of the whole centrifugal compressor flow passage including impeller and diffuser. The whole optimization design system was integrated based on iSIGHT, a commercial integration and optimization software, which provides a direct application of some optimization algorithms. To insure the practicability of optimization, the performance of centrifugal compressor under all condition was concerned during the optimizing process. That means a compositive object function considering the aerodynamic efficiency, pressure ratio and mass flow rate under different work condition was applied by using different weight number for different conditions. Using the optimization method described in this paper, an optimized design of the impeller blade of centrifugal compressor was obtained. Comparing to the original design, optimized design has a better performance not only under the design work condition, but also the off-design work condition including near stall and near choke condition.

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DEVELOPMENT OF AERODYNAMIC SHAPE OPTIMIZATION TOOLS FOR MULTIPLE-BODY AIRCRAFT GEOMETRIES OVER TRANSONIC TURBULENT FLow REGIME (천음속 난류 유동장에서의 다중체 항공기 형상의 공력 설계 도구의 개발)

  • Lee, B.J.;Lee, J.S.;Yim, J.W.;Kim, Chong-Am
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.100-110
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    • 2007
  • A new design approach for a delicate treatment of complex geometries such as a wing/body configuration is arranged using overset mesh technique under large scale computing environment for turbulent viscous flow. Various pre- and post-processing techniques which are required of overset flow analysis and sensitivity analysis codes are discussed for design optimization problems based on gradient based optimization method (GBOM). The overset flow analysis code is validated by comparing with the experimental data of a wing/body configuration (DLR-F4) from the 1st Drag Prediction Workshop (DPW-I). In order to examine the applicability of the present design tools, careful design works for the drag minimization problem of a wing/body configuration are carried out by using the developed aerodynamic shape optimization tools for the viscous flow over multiple-body aircraft geometries.

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A Tailless UAV Multidisciplinary Design Optimization Using Global Variable Fidelity Modeling

  • Tyan, Maxim;Nguyen, Nhu Van;Lee, Jae-Woo
    • International Journal of Aeronautical and Space Sciences
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    • v.18 no.4
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    • pp.662-674
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    • 2017
  • This paper describes the multidisciplinary design optimization (MDO) process of a tailless unmanned combat aerial vehicle (UCAV) using global variable fidelity aerodynamic analysis. The developed tailless UAV design framework combines multiple disciplines that are based on low-fidelity and empirical analysis methods. An automated high-fidelity aerodynamic analysis is efficiently integrated into the MDO framework. Global variable fidelity modeling algorithm manages the use of the high-fidelity analysis to enhance the overall accuracy of the MDO by providing the initial sampling of the design space with iterative refinement of the approximation model in the neighborhood of the optimum solution. A design formulation was established considering a specific aerodynamic, stability and control design features of a tailless aircraft configuration with a UCAV specific mission profile. Design optimization problems with low-fidelity and variable fidelity analyses were successfully solved. The objective function improvement is 14.5% and 15.9% with low and variable fidelity optimization respectively. Results also indicate that low-fidelity analysis overestimates the value of lift-to-drag ratio by 3-5%, while the variable fidelity results are equal to the high-fidelity analysis results by algorithm definition.

AERODYNAMIC DESIGN OPTIMIZATION OF ROTOR BLADE OA AIRFOILS (로터 블레이드 OA 익형의 공력 최적 설계)

  • Sa, J.H.;Park, S.H.;Kim, C.J.;Yun, C.Y.;Kim, S.H.;Kim, S.;Yu, Y.H.
    • Journal of computational fluids engineering
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    • v.14 no.2
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    • pp.25-31
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    • 2009
  • Numerical optimization of rotor blade airfoils is performed with a response surface method for helicopter rotor. For the baseline airfoils, OA 312, OA 309, and OA 407 airfoils are selected and optimized to improve aerodynamic performance. Aerodynamic coefficients required for the response surface method are obtained by using Navier-Stokes solver with k-$\omega$ Shear Stress Transport turbulence model. An optimized airfoil has increased drag divergence Mach number. The present design optimization method can generate an optimized airfoil with multiple design constraints, whenever it is designed from different baseline airfoils at the same design condition.

MULTI-STAGE AERODYNAMIC DESIGN OF AIRCRAFT GEOMETRIES BY KRIGING-BASED MODELS AND ADJOINT VARIABLE APPROACH (Kriging 기반 모델과 매개변수(Adjoint Variable)법을 이용한 항공기형상의 2단계 공력최적설계)

  • Yim, J.W.;Lee, B.J.;Kim, C.
    • 한국전산유체공학회:학술대회논문집
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    • 2009.04a
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    • pp.57-65
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    • 2009
  • An efficient and high-fidelity design approach for wing-body shape optimization is presented. Depending on the size of design space and the number of design of variable, aerodynamic shape optimization process is carried out via different optimization strategies at each design stage. In the first stage, global optimization techniques are applied to planform design with a few geometric design variables. In the second stage, local optimization techniques are used for wing surface design with a lot of design variables to maintain a sufficient design space with a high DOF (Degree of Freedom) geometric change. For global optimization, Kriging method in conjunction with Genetic Algorithm (GA) is used. Asearching algorithm of EI (Expected Improvement) points is introduced to enhance the quality of global optimization for the wing-planform design. For local optimization, a discrete adjoint method is adopted. By the successive combination of global and local optimization techniques, drag minimization is performed for a multi-body aircraft configuration while maintaining the baseline lift and the wing weight at the same time. Through the design process, performances of the test models are remarkably improved in comparison with the single stage design approach. The performance of the proposed design framework including wing planform design variables can be efficiently evaluated by the drag decomposition method, which can examine the improvement of various drag components, such as induced drag, wave drag, viscous drag and profile drag.

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Multi-Point Aerodynamic Shape Optimization of Rotor Blades Using Unstructured Meshes

  • Lee, Sang-Wook;Kwon, Oh-Joon
    • International Journal of Aeronautical and Space Sciences
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    • v.8 no.1
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    • pp.66-78
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    • 2007
  • A multi-point aerodynamic shape optimization technique has been developed for helicopter rotor blades in hover based on a continuous adjoint method on unstructured meshes. The Euler flow solver and the continuous adjoint sensitivity analysis were formulated on the rotating frame of reference. The 'objective function and the sensitivity were obtained as a weighted sum of the values at each design point. The blade section contour was modified by using the Hicks-Henne shape functions. The mesh movement due to the blade geometry change was achieved by using a spring analogy. In order to handle the repeated evaluation of the design cycle efficiently, the flow and adjoint solvers were parallelized based on a domain decomposition strategy. A solution-adaptive mesh refinement technique was adopted for the accurate capturing of the wake. Applications were made to the aerodynamic shape optimization of the Caradonna-Tung rotor blades and the UH-60 rotor blades in hover.