Review of Boundary Conditions and Investigation Towards the Development of a Growth Model: a Lattice Boltzmann Method Approach

Identifier:  TDX:2403

Handle: https://hdl.handle.net/20.500.11797/TDX2403

Authors:  Puig Arànega, Albert

Abstract:
The lattice Boltzmann method (LBM) is a computational fluid dynamics technique that is rapidly earning popularity due to its inherent properties: it deals with complex geometries with relative ease, it is computationally easy to implement and it can be effectively used with massive parallel computing tools. However, the method is still not entirely established in the scientific community due to its relatively early appearance. One known topic that is still under active research are the study and development of effective boundary conditions, specially non-reflecting ones. We can find on the literature several proposals of non-reflective boundary conditions for LBM. However, there is not much conducted research about the physical impact of using a reflective or a non-reflective approach on a simulation beyond the boundary tests. On the other hand, the LBM is also capable to able to hold the advection-diffusion transport equation by means of a passive scalar. One very active topic is the study of the blood platelet transport. Platelets are the cornerstone of the coagulation and this latter phenomenon can occlude an artery when platelets are activated in an atherosclerotic artery, which is called thrombosis. Platelets also experiment a spontaneous migration, called margination, to the walls that naturally enhance their performance. The thesis report consists on two distinct parts. Firstly, we present the results of a parametric study to analyze the physical impact of the spurious reflections that occur on a flow past a square obstacle in a confined channel. Secondly, we develop a transport model for platelets in the LBM based on the double distribution technique and we reproduce the margination of platelets and we prepare a set of tools to develop a growth model to resemble a thrombosis event in a coronary artery.