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- Type of Document: Ph.D. Dissertation
- Language: Farsi
- Document No: 53409 (08)
- University: Sharif University of Technology
- Department: Mechanical Engineering
- Advisor(s): Taghizadeh Manzari, Mehrdad
- Abstract:
- The main goal of this study is simulation of the flow-like landslide phenomenon and investigation of the effect of bed material entrainment on its behavior. Debris flows are considered as one of the types of flow-like landslides, and flow of dry granular materials on horizontal and inclined beds as a simple model of these types of flows in nature is numerically simulated. Also, in order to investigate the effect of entrainment on dynamics of flow, a bed containing granular materials is installed on horizontal and inclined beds. The governing equations of the flow are solved in the continuum context using the Smoothed Particle Hydrodynamics (SPH) method and the depth-averaged assumptions are not used. To simulate the behavior of granular material, viscoplastic constitutive model is used. Initially, to evaluate the effects of entrainment on dynamics of flow, variations in energy and momentum of materials of flow are studied. It is observed that although the entrainment can reduce the maximum velocity of flow, this phenomenon can increase the momentum of the flow by increasing its moving mass. Also, it is shown that although entrainment can facilitate the conversion of potential energy to kinetic energy, it increases the cumulative dissipated energy. Next, the granular mixture formed at the interface between the flow and the bed material due to the entrainment is modeled using a generalized viscoplastic model and the effects of applying this model on dynamics of flow are investigated. It is observed that the effect of applying this model on the dynamics of flow depends on the relative properties of the flow and bed materials. Also, by comparing the entrainment rate formulas used in depth-averaged methods with the results of complete solution of governing equations of flow using SPH method, it is shown that these formulas can not model material deposition during flow motion. Finally, the debris flow on real 3D topography is simulated
- Keywords:
- Debris Flow ; Entrainment ; Smoothed Particle Hydrodynamics (SPH) ; Granular Materials ; Continuum Mechanics ; Numerical Simulation ; Viscoplastic Rheology
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