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A Unified Fve-Ale Approach to Solve Unsteady Laminar to Turbulent Flow on Moving Boundary Domains

Naderi, Alireza | 2009

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 39460 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Darbandi, Masoud; Taeibi Rahni, Mohammad
  7. Abstract:
  8. In this study, an arbitrary Lagrangian-Eulerian (ALE) approach is incorporated with a mixed finite- volume-element (FVE) method to establish a novel moving boundary algorithm to simulate unsteady incompressible flow on non-stationary meshes. The method collects the advantages of both finite-volume and finite-element methods as well as the ALE approach in a unified algorithm capable of solving laminar, transient, and turbulent flows in fluid flow problems with moving boundaries. To enhance the robustness of the extended algorithm, we treat the convection terms at the cell faces using a physical influence upwinding scheme, while the diffusion terms are treated using bilinear finite-element shape functions. On the other hand, the performance of ALE approach is improved by using the Laplace method in our mesh moving strategy. This strategy is readily applicable to hybrid grids involving triangular and quadrilateral elements distributed in a domain, either partially or entirely. The use of hybrid finite-element grids increases the capability of the method remarkably. To show the robustness of the unified algorithm, we examine both first- and the second-order temporal stencils. In simulating turbulent flow fields, we have included the Spalart-Allmaras, standard , and models in our algorithm. To show the robustness of the extended method, we solve laminar to turbulent flow in a few internal and external flow cases. Furthermore, we also solve the deep stall and transient phenomena to illustrate the capability of the extended method in complex fluid flow problems with moving boundaries. The current results show that the accuracy of the current unified method is great, despite using very coarse meshes and very large time steps
  9. Keywords:
  10. Moving Boundary ; Moving Mesh ; Finite Element Method ; Turbulent Flow ; Transition Flow ; Hybrid Mesh ; Finite Volume Method ; Arbitrary Lagrangian-Eulerian Method

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