• Title/Summary/Keyword: transonic

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Aeroelastic Analysis of a Wing with Freeplay Considering Effects of Angle-of-Attack (받음각 효과를 고려한 유격이 있는 날개의 공탄성 해석)

  • Kim Jong-Yun;Yoo Jae-Han;Park Young-Keun;Lee In
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2005.04a
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    • pp.295-300
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    • 2005
  • The freeplay, one of the concentrated structural nonlinearities, is inevitable for control surfaces of a real air vehicle due to normal wear of components and manufacturing mismatches. Also aerodynamic nonlinearities caused by a shock wave occur in transonic region. In practice, these nonlinearities induce the limit cycle oscillation (LCO) and decrease the transonic flutter speed. In this study, the fictitious mass method is used to apply a modal approach to nonlinear structural models due to freeplay. The transonic small-disturbance (TSD) equation is used to calculate unsteady aerodynamic forces in transonic region. Nonlinear aeroelastic time responses are predicted by the coupled time integration method (CTIM). This method was also applied to a 3D all-movable control wing to investigate its nonlinear aeroelastic responses. The angle of attack effect on the LCO characteristics has been found to be closely related with the initial pitching moment.

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Flutter characteristics of a Composite Wing with Various Ply Angles (복합재료날개의 적층각에 대한 플러터 특성 연구)

  • Yoo, Jae-Han;Kim, Dong-Hyun;Lee, In
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.04a
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    • pp.126-130
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    • 2000
  • In this study, flutter characteristics of a composite wing have been studied for the variation of laminate angles in the subsonic, transonic and supersonic flow regime. The laminate angles are selected by the aspect of engineering practice such as 0, $\pm$45 and 90 degrees. To calculate the unsteady aerodynamics for flutter analysis, the Doublet Lattice Method(DLM) in subsonic flow and the Doublet Point Method(DPM) in supersonic flow are applied in the frequency domain. In transonic flow, transonic small disturbance(TSD) code is used to calculate the nonlinear unsteady aerodynamics in the time domain. Aeroelastic governing equation has been solved by v-g method in the frequency domain and also by Coupled Time-Integration Method(CTIM) in the time domain. from the results of present study, characteristics of free vibration responses and aeroelastic instabilities of a composite wing are presented for the set of various lamination angles in the all flow range.

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Drag Assessment of Transonic Missile due to Engine Plume (엔진화염에 따른 천음속 유도탄의 항력 평가)

  • Ahn C. S;Jung S. Y
    • Journal of computational fluids engineering
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    • v.8 no.3
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    • pp.7-11
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    • 2003
  • Accurate assessment of the effect of jet plume on the boattail pressure drag of transonic airbreathing missiles is very important to reduce drag and to satisfy the flight range and the required maneuver. Numerical results of drag analysis for boattail and base pressures due to jet plume are presented considering the turbulence modeling. Drag assessment due to the size of jet plume, the conditions of the exhaust gas, the configurations of the boattail, and transonic mach numbers is included.

Transonic/Supersonic Flutter Analysis of a Fighter Wing with Tip-Store (끝단 장착물이 있는 항공기 날개의 천음속/초음속 플러터 해석)

  • Kim, Dong-Hyun;Lee, In
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1198-1203
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    • 2000
  • In this study, a nonlinear aeroelastic analysis system for the fighter wing with tip-store has been developed additionally in the transonic and supersonic flow region. The unsteady CFD code based on the transonic small disturbance theory has been incorporated to consider the numerical capability for the aerodynamic nonlinear effects. The coupled time-integration method is used to observe the detailed nonlinear aeroelastic responses for elastic wings in their flight. condition. A conservative wing-box model of a fighter wing with tip-store is modeled by MSC/PATRAN and the corresponding free vibration analysis has been performed by MSC/NASTRAN. The results of flutter analyses are presented in the subsonic, transonic and supersonic flow regime.

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TRANSONIC AEROELASTIC ANALYSIS OF LEARJET AIRCRAFT WING MODEL (리어제트 항공기 날개의 천음속 공탄성해석)

  • Tran, T.T.;Kim, D.H.;Kim, Y.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2011.05a
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    • pp.453-457
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    • 2011
  • In this study, transonic aeroelastic response analyses haw been conducted for the business jet aircraft configuration considering shockwave and flow separation effects. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to wing-body configurations. In transonic flight region, the characteristics of static and dynamic aeroelastic responses have been investigated for a typical wing-body configuration model. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.

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Numerical Study of the Flow in a Transonic Centrifugal Compressor (천음속 원심압축기 내부 유동의 수치해석)

  • Seong, Seon-Mo;Kang, Shin-Hyoung
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.228-231
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    • 2008
  • Flow fields of a transonic centrifugal compressor are calculated using the commercial CFD code, CFX-TASCflow. Due to the transonic inlet condition, interactions between the shock wave and boundary layers and between the shock wave and tip leakage vortices generate complex flow structures and extra losses. The calculated results show that strong secondary flows due to high curvature and high rotational speed of the impeller. And streamlines near suction surface show that strong radially upward flow develops after the shock between the leading edge locations of main blade and splitter.

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Transonic Aeroelastic Analysis of Business Jet Aircraft Wing Model (비즈니스 제트 항공기 날개의 천음속 공탄성 해석)

  • Kim, Yo-Han;Kim, Dong-Hyun;Tran, Thanh-Toan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.299-299
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    • 2011
  • In this study, transonic aeroelastic response analyses have been conducted for the business jet aircraft configuration considering shockwave and flow separation effects. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to wing-body configurations. In transonic flight region, the characteristics of static and dynamic aeroelastic responses have been investigated for a typical wing-body configuration model. Also, it is typically shown that the current computation approach can yield realistic and practical results for aircraft design and test engineers.

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Aeroelastic Analyses of Space Rocket Configuration Considering Viscosity Effects (유동점성효과를 고려한 우주발사체 형상의 천음속 공탄성해석)

  • Kim, Yo-Han;Kim, Dong-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.64-71
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    • 2011
  • In this study, steady and unsteady aerodynamic analyses of a huge rocket configuration have been conducted in a transonic flow region. The launch vehicle structural response are coupled with the transonic flow state transitions at the nose of the payload fairing. The developed fluid-structure coupled analysis system is applied for aeroelastic computations combining computational structural dynamics(CSD), finite element method(FEM) and computational fluid dynamics(CFD) in the time domain. It can give very accurate and useful engineering data on the structural dynamic design of advanced flight vehicles. For the nonlinear unsteady aerodynamics in high transonic flow region, Navier-Stokes equations using the structured grid system have been applied to the rocket configurations. Also, it is typically shown that the current computation approach can yield realistic and practical results for rocket design and test engineers.

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Design Optimization of Transonic Airfoils Based on the Navier-Stokes Equation (Navier-Stokes 방정식을 이용한 천음속 익형의 설계최적화 연구)

  • Lee Hyeong Min;Jo Chang Yeol
    • 한국전산유체공학회:학술대회논문집
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    • 1999.05a
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    • pp.177-185
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    • 1999
  • The airfoil design optimization procedures based on the Navier-Stokes equations were developed, This procedure enables more realistic and practical transonic airfoil designs. The modified Hicks-Henne functions were used to generate the shape of airfoils. Five Hick-Henne functions were used to design upper surface of airfoil only. To enhance the ability of Hick-Henne function to generate various airfoil shape with limited number of functions, the positions of control points were adjusted through optimization procedure. The design procedure was applied to the single-point design for the drag minimization problem with lift and area constraints. The result shows the capability of the procedure to generate much realistic airfoils with very small drag-creep in the low transonic regime. This is mainly due to the viscosity effect of Navier-Stokes flow analysis. However, in the higher transonic range tile drag-creep appears. The multi-point design is shown to be an effective way to avoid the drag-creep and improve off-design performance which is very similar in the Euler design.

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Aerodynamic Design and Numerical Analysis on a Transonic Centrifugal Compressor (천음속 원심압축기의 공력설계 및 수치해석)

  • Choi, Jae-Ho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.4
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    • pp.56-62
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    • 2008
  • This study presents the aerodynamic design and numerical analysis results on a transonic centrifugal compressor which is used for gas turbine systems. Mean-line analysis and quasi-3D analysis are used for the aerodynamic design, and Reynolds-averaged Navier-Stokes analysis is applied to flow analysis of the compressor. The aerodynamic parameters for a transonic compressor, such as pressure coefficient, swirl parameter, blade loading, are discussed, and flow characteristics in the impeller and diffuser are discussed.