Tesi di LAUREA SPECIALISTICA Titolo Fluid dynamics in an abdominal aortic aneurysm with Large Eddy Simulation and backflow stabilization Data 2016-09-16 Autore/i Le Van, Davide Relatore Formaggia, l. Relatore Vergara, C. Full text non disponibile Abstract In recent years, several studies on Abdominal Aortic Aneurysms (AAA) have been carried out using mathematical and numerical modeling with real geometries. Some of them focused on the presence of transitional and turbulent processes and on their consequences on the evolution on the disease. Most of these works use RANS models to study these processes. However, more accurate models can be found in the Large Eddy Simulation (LES) category. The goal of this work is the study of the fluid dynamics inside the AAA using computational fluid dynamics (CFD) with a recently proposed LES model called sigma model. This is used to analyze the presence of transitional effects in a real aneurysm geometry. Moreover, the simulation of several heartbeats allows to evaluate in which phases of the cardiac cycles there are significant velocity fluctuations. We have also analyzed the numerical issue of backflow instability, commonly found in cardiovascular problems. To treat it, a particular stabilization procedure has been implemented in LIFEV C++ library.