Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.506024
Title: Interface Tracking and Solid-Fluid Coupling Techniques with Coastal Engineering Applications
Author: Mindel, Julian Eduardo
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2008
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Abstract:
Multi-material physics arise in an innumerable amount of engineering problems. A broadlyscoped numerical model is developed and described in this thesis to simulate the dynamic interactionof multi-fluid and solid systems. It is particularly aimed at modelling the interactionof two immiscible fluids with solid structures in a coastal engineering context; however it canbe extended to other similar areas of research. The Navier Stokes equations governing thefluids are solved using a combination of finite element (FEM) and control volume finite element(CVFE) discretisations. The sharp interface between the fluids is obtained through thecompressive transport of material properties (e.g. material concentration). This behaviour isachieved through the CVFE method and a conveniently limited flux calculation scheme basedon the Hyper-C method by Leonard (1991). Analytical and validation test cases are provided,consisting of steady and unsteady flows. To further enhance the method, improve accuracy, andexploit Lagrangian benefits, a novel moving mesh method is also introduced and tested. It isessentially an Arbitrary Lagrangian Eulerian method in which the grid velocity is defined bysemi-explicitly solving an iterative functional minimisation problem. A multi-phase approach is used to introduce solid structure modelling. In this approach,solution of the velocity field for the fluid phase is obtained using Model B as explained byGidaspow (1994, page 151). Interaction between the fluid phase and the solids is achievedthrough the means of a source term included in the fluid momentum equations. The interactingforce is calculated through integration of this source term and adding a buoyancy contribution. The resulting force is passed to an external solid-dynamics model such as the Discrete ElementMethod (DEM), or the combined Finite Discrete Element Method (FEMDEM).The versatility and novelty of this combined modelling approach stems from its ability tocapture the fluid interaction with particles of random size and shape. Each of the three maincomponents of this thesis: the advection scheme, the moving mesh method, and the solid interactionare individually validated, and examples of randomly shaped and sized particles areshown. To conclude the work, the methods are combined together in the context of coastal engineeringapplications, where the complex coupled problem of waves impacting on breakwateramour units is chosen to demonstrate the simulation possibilities. The three components developedin this thesis significantly extend the application range of already powerful tools, suchas Fluidity, for fluids-modelling and finite discrete element solids-modelling tools by bringingthem together for the first time.
Supervisor: Latham, John-Paul ; Munjiza, Antonio ; Pain, Christopher Sponsor: EPSRC ; Sogreah ; CLI ; Baird Associates
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.506024  DOI: Not available
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