An Implicit Algorithm for Numerical Simulation of Large Deformation Structures with Incompressible Fluid Flow

Fouladi, Nematollah | 2013

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 44736 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Darbandi, Masoud
  7. Abstract:
  8. The fluid structure interaction (FSI) problems are widely encountered in many industrial applications in mechanical, aerospace, biomedical, marine, and wind engineering. The main contributions of this research are focused on simulating flow with moving or deforming boundaries including FSI problems with large movement or deformations. In this regard, a hybrid finite-element-volume (FEV) method was used in an arbitrary Lagrangian-Eulerian (ALE) framework. In this research, a new layer-by-layer mesh movement strategy was developed to perform the unstructured grid movement more robustly. This strategy converts the complex data structure of an unstructured grid to a simple quasi-structured data structure (QSDS) one and moves the grid using basic spring analogy (SA) method in a layer-by-layer manner very smoothly and efficiently. To show the robustness of our numerical strategy, the simulations are provided for two well-known flow induced vibration (FIV) problems, i.e., the vortex induced vibration of an elastic circular cylinder and the flutter of a bridge section. Additionally, this research presents and simulates a new FSI problem, i.e., the FIV of two elastic/flexible plates hinged to the two ends of a fixed flat plate in a cross flow. Then, we carefully study the dynamic behavior of two elastic/flexible plates, which are in direct interaction with the generated von Karman vortex street. The results show that the oscillation of elastic plates experience three situations of out of phase, transition and in-phase dynamic behaviors. Additionally, the two elastic/flexible plates perform similar dynamic behavior but with some phase lag. The phase lag is equal to the phase lag between von-Karman upper and lower generated vorticities. This test can be considered as a new benchmark case to be used for validating the new developed numerical methods. Similar to past FIV problems, this novel test also reveals two important lock-in and phase-switch phenomena. The achieved results show that the current developed FEV-ALE SA-QSDS strategy provides accurate solutions for the FSI problems despite experiencing very large grid deformations and movements
  9. Keywords:
  10. Fluid-Structure Interaction ; Moving Boundary ; Quasi-Structured Data Structure ; Layer-by-Layer Mesh Movement ; Finite Volume Element Method ; Arbitrary Lagrangian-Eulerian Method ; Elastic Deformation ; Moving Mesh

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