Develop the Multigrid Method to Solve the Hydrodynamics Problems<br/>

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Develop the Multigrid Method to Solve the Hydrodynamics Problems

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 40151 (08)
University: Sharif University of Technology
Department: Mechanical Engineering
Advisor(s): Noori, Ali; Seif, Mohammad Saeed
Abstract:
In recent years, many advanced Computational Fluid Dynamics (CFD) methods have been developed for accurate and efficient simulation of fluid flow. The application of these methods shows that for sufficient accuracy, the mesh resolution has to be reasonably high. Unfortunately, conventioanal single-grid Navier-Stokes solvers suffer from poor convergence characteristics. For this problem we used Multigrid method to speed up the convergence rate. In this section a code was developed (based on the conventional CFD algorithm) which can solve Navier-Stokes equations on structured grids. It also simulates the free surface by VOF method. Agglomeration multigrid method is used in present study for coarsening. For this reason it is needed to apply the unstructured grid as well. Fractional step method is used in present study so we need to solve the Poisson equation with multigrid method. The present numerical method is applied to some test cases to evaluate the accuracy and efficiency of the code. It is found that multigrid method could speed the convergence rate, up to 3 times. By comparison the V and W cycles with varios grids, it seems that W cycle act better in most cases
Keywords:
Multigrid Method ; Finite Volume Method ; Unstructured Grid ; Computational Fluid Dynamics (CFD)

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