• Title/Summary/Keyword: Preconditioned Wavier-Stokes Equations

Search Result 4, Processing Time 0.017 seconds

Preconditioned Multistage Time Stepping for the Multigrid Method (다중 격자 기법을 위한 예조건화된 다단계 시간 전진 기법)

  • Kim Yoonsik;Kwon Jang Hyuk
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2001.05a
    • /
    • pp.127-133
    • /
    • 2001
  • In this paper, the preconditioned multistage time stepping methods which are popular multigrid smoothers is studied for the compressible flow calculations. Fourier analysis on the local time stepping and block-Jacobi preconditioned residual operators is performed using the linearized 2-D Navier-Stokes equations. It fumed out that block-Jacobi preconditioner has better performance in eigenvalue clustering. They are implemented in the 2-D compressible Euler and Wavier-Stokes calculations with multigrid methods to verify that the block-Jacobi preconditioned multistage time stepping shows better performance in convergence acceleration.

  • PDF

Convergence Acceleration Methods for the Multigrid Navier-Stokes Computation (다중 격자 Wavier-Stokes 해석의 수렴성 증진 기법)

  • Kim Yoonsik;Kwon Jang Hyuk;Choi Yun Ho;Lee Seungsoo
    • Proceedings of the KSME Conference
    • /
    • 2002.08a
    • /
    • pp.35-38
    • /
    • 2002
  • The convergence acceleration methods for the compressible Wavier-Stokes equations are studied ,which are multigrid method and implicit preconditioned multistage time stepping method. In this paper, the performance of implicit preconditioning methods are studied for the full-coarsening multigrid methods on the high Reynolds number compressible flow computations. The effect of numerical flux on the convergence are investigated for the inviscid and viscous calculations.

  • PDF

Computation of Non-reacting and Reacting Flow-Fields Using a Preconditioning Method (예조건화기법을 이용한 유동장 및 반응유동장의 계산)

  • Ko Hyun;Yoon Woong-Sup
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2001.05a
    • /
    • pp.189-194
    • /
    • 2001
  • In this paper, non-reacting and reacting flowfields were computed using a preconditioned Navier-Stokes solver. The preconditioning technique of Merkle et al. and TVD scheme or Chakravarthy and Osher was employed and the results obtained using developed code have a good agreement with the previous results and experimental data. The preconditioned Wavier-Stokes equation set with low Reynolds number $\kappa-\epsilon$ equation and species continuity equations, are discretized with strongly implicit manner and time integrated with LU-SSOR scheme. For the purpose of treating unsteady problem the duel-time stepping scheme was employed. For the validation of the code in incompressible flow regime, steady driven square cavity flow was considered and calculation result shows reasonably good agreement with the result of incompressible code. Shock wave/boundary layer interaction problem was considered to show the shock capturing performance of preconditioned-TVD scheme. To validate unsteady flow, acoustic oscillation problem was calculated, and supersonic premix flame of $H_2$-air reaction problem which is calculated with turbulence model, 9-species/18-reaction step reaction model, shows reasonable agreement with the previous results. As a result, the preconditioning method has an advantage to calculate incompressible and compressible flow through one code and preconditioned solver easily developed from standard compressible code with minor efforts. But additional computational time and computer memory is required due to preconditioning matrix.

  • PDF

AERODYNAMICS OF THE RAE 101 AIRFOIL IN GROUND EFFECT WITH THE OVERLAPPED GRID (중첩 격자 기법을 이용한 지면 효과를 받는 RAE 101 익형의 공력 해석)

  • Lee, J.E.;Kim, Y.;Kim, E.;Kwon, J.H.
    • 한국전산유체공학회:학술대회논문집
    • /
    • 2006.10a
    • /
    • pp.193-198
    • /
    • 2006
  • It takes a lot of time and effort to generate grids for numerical analysis of problems with ground effect because the relative attitude and height of airfoil should be maintained to the ground as well as the inflow. A low Mach number preconditioned turbulent flow solver using the overlap grid technique has been developed and applied to the ground effect simulation. It has been validated that the present method using the multi-block grid gives us highly accurate solutions comparing with the experimental data of the RAE 101 airfoil in an unbounded condition. Present numerical method has been extended to simulate ground effect problems by using the overlapped grid system to avoid tedious work in generating multi-block grid system. An extended method using the overlapped grid has been verified and validated by comparing with results of multi-block method and experimental data as well. Consequently, the overlapped grid method can provide not only sufficiently accurate solutions but also the efficiency to simulate ground effect problems. It is shown that the pressure and aerodynamic centers move backward by the ground effect as the airfoil approaches to the ground.

  • PDF