Simulation of Self-Propulsive Phenomenon, Using Lattice Boltzmann Method

Beigzadeh Abbassi, Mohammad Reza | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41494 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Tayyebi Rahni, Mohammad; Taghizadeh Manzari, Mehrdad
  7. Abstract:
  8. Many human inventions are inspired by nature, such as fish swimming, bird/insect flight, etc. A basic consideration for the design of swimming machines is the design of propulsors. A creative design of propulsors can be inspired by fish locomotion. The term locomotion means that thrust is generated by undulation of fish body. Thus, there is no need to have an external propulsor. We need to understand how thrust is obtained by fish locomotion. In this study, sub-carangiform motion, which is a well known locomotion and which is practiced by most fish, is simulated numerically using Lattice Boltzmann method (LBM). To simulate the geometry of fishlike body, the profile of a flexible airfoil was used. Note, we deal here with an incompressible unsteady flow. The results show vortex pairs in the wake of the oscillating flexible airfoil, which are very similar to Von-Kármán vortices. Of course, the vortices generated here are in one line (different from Von-Kármán vortices in the wake of a cylinder, which are in two lines). Also, the results show that lattice Boltzmann method, accompany with modified boundary conditions for curved solid boundaries, can accurately simulate the variation of drag coefficient with time. The velocity profiles and vortex structures are shown to be close to other reliable numerical results
  9. Keywords:
  10. Lattice Boltzmann Method ; Moving Boundary ; Unsteady Flow ; Locomotion ; Curved Boundary Condition ; Bounce-Back Boundary Condition ; Carangiform Motion

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