• Title/Summary/Keyword: von Neumann stability analysis

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Convergence and Stability Analysis of LU Scheme on Unstructured Meshes: Part II - Navier-Stokes Equations (비정렬 격자계에서 LU implicit scheme의 수렴성 및 안정성 해석: Part II - Navier-Stokes 방정식)

  • Kim, Joo-Sung;Kwon, Oh-Joon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.8
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    • pp.1-11
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    • 2004
  • A comprehensive study has been made for the investigation of the convergence and stability characteristics of the LU scheme for solving the Navier-Stokes equations on unstructured meshes. For this purpose the characteristics of the LU scheme was initially studied for a scalar model equation. Then the analysis was extended to the Navier-Stokes equations. It was shown that the LU scheme has an inherent stiffness in the streamwise direction. This stiffness increases when the grid aspect ratio becomes high and the cell Reynolds number becomes small. It was also shown that the stiffness related to the grid aspect ratio can be effectively eliminated by performing proper subiteration. The results were validated for a flat-plate turbulent flow.

Convergence Analysis of LU Scheme for the Euler Equations on Unstructured Meshes

  • Kim Joo Sung;Kwon Oh Joon
    • 한국전산유체공학회:학술대회논문집
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    • 2003.10a
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    • pp.175-177
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    • 2003
  • The convergence characteristics of the LV scheme for the Euler equations have been investigated by using the Von Neumann stability analysis. The results indicated that the convergence rate is governed by a specific combination of CFD parameters. Based on this insight, it is shown that the convergence characteristics of the LV scheme is not deteriorated at any grid aspect-ratio as long as the local time step is defined based on the parameter combination. The numerical results demonstrated that this time step definition provide a uniform convergence for grid aspect-ratios between one to$1{\times}10^{4}$.

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COLLOCATION METHOD USING QUARTIC B-SPLINE FOR NUMERICAL SOLUTION OF THE MODIFIED EQUAL WIDTH WAVE EQUATION

  • Islam, Siraj-Ul;Haq, Fazal-I;Tirmizi, Ikram A.
    • Journal of applied mathematics & informatics
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    • v.28 no.3_4
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    • pp.611-624
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    • 2010
  • A Numerical scheme based on collocation method using quartic B-spline functions is designed for the numerical solution of one-dimensional modified equal width wave (MEW) wave equation. Using Von-Neumann approach the scheme is shown to be unconditionally stable. Performance of the method is validated through test problems including single wave, interaction of two waves and use of Maxwellian initial condition. Using error norms $L_2$ and $L_{\infty}$ and conservative properties of mass, momentum and energy, accuracy and efficiency of the suggested method is established through comparison with the existing numerical techniques.