• Title/Summary/Keyword: Mixed Explicit-Implicit Galerkin Method

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A Numerical Study on Shock Wave Turbulent Boundary Layer Interactions in High-Speed Flows (고속 흐름에서의 충격파와 난류경계층의 상호작용에 관한 수치적 연구)

  • Mun, Su-Yeon;Son, Chang-Hyeon;Lee, Chung-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.3
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    • pp.322-329
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    • 2001
  • A study of the shock wave turbulent boundary layer interaction is presented. The focus of the study is the interactions of the shock waves with the turbulent boundary layer on the falt plate. Three examples are investigated. The computations are performed, using mixed explicit-implicit generalized Galerkin finite element method. The linear equations at each time step are solved by a preconditioned GMRES algorithm. Numerical results indicate that the implicit scheme converges to the asymptotic steady state much faster than the explicit counterpart. The computed surface pressures and skin friction coefficients display good agreement with experimental data. The flowfield manifests a complex shock wave system and a pair of counter-rotating vortices.

A Study on Flowfield-Dependent Mixed Explicit-Implicit Method in Heat and Fluid Dynamics Problems (유동변수 파라미터에 의한 혼합 내-외재적 열-유동장 수치해석 방법 연구)

  • Mun, Su-Yeon;Song, Chang-Hyeon;Lee, Chung-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.7
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    • pp.989-996
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    • 2001
  • High-speed and low-speed flows are simulated numerically by flowfield-dependent mixed explicit-implicit (FDMEI) method. This algorithm depends on implicitness parameters of convection, diffusion, diffusion gradients, and source terms which are calculated from the changes of local Mach, Reynolds, Peclet, and Damkohler numbers between adjacent nodes. Convection phenomena or shock waves are resolved from Mach number-dependent implicitness parameters whereas diffusion or viscous actions are simulated by Reynolds number or Peclet number-dependent implicitness parameters. Fluctuation components of all variables are properly accommodated spatially and temporally in the FDMEI procedure. To illustrate, some benchmark example problems are presented for comparisons of the FDMEI results with other available data. These results appear to be encouraging and point toward the need for further investigations of the FDMEI theory.

NUMERICAL SIMULATION OF HIGH-SPEED FLOWS WITH SHOCK WAVE TURBULENT BOUNDARY LAYER INTERACTIONS (충격파와 난류경계층의 상호작용에 대한 수치해석)

  • Moon S. Y.;Sohn C. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2000.05a
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    • pp.51-59
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    • 2000
  • The Interactions of shock wave with turbulent boundary layers in high-speed flows cause complex flowfields which result in increased adverse pressure gradients, skin friction and temperature. Accurate and reliable prediction of such phenomena is needed in designing high-speed propulsion systems. Such analyses of the complex flowfields require sophisticated numerical scheme that can resolve interactions between shock wave and boundary layers accurately. Therefore the purpose of the present. article is to introduce an accurate and efficient mixed explicit-implicit generalized Galerkin finite element method. To demonstrate the validity of the theory and numerical procedure, several benchmark cases are investigated.

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