Multiscale modeling of hemodynamics in microvessels

• Κύριος συγγραφέας: Γιαννοκώστας, Κωνσταντίνος
• Άλλοι συγγραφείς: Giannokostas, Konstantinos
• Γλώσσα: English
• Έκδοση: 2022
• Θέματα: Blood; Hemodynamics; Hemorheology; Rheology; Hematocrit; Viscoplastic fluids; Thixotropy; Blood plasma; Computational fluid dynamics; Vasodilatation; Aneurysms; Αίμα; Βιορευστομηχανική; Αιμορρεολογία; Ρεολογία; Ρευστομηχανική; Ιξωδοελαστικά υλικά; Αιμοδυναμική; Μικροκυκλοφορία; Πλάσμα αίματος; Θιξοτροπία; Αγγειοδιαστολή

Blood is a complex suspension of red and white cells, and platelets in an aqueous solution, the so-called plasma, containing dissolved proteins. In the last decades, the investigation of hemorheology has stimulated a lot of attention to the complex mechanical behavior of blood primarily due to the direct relevance of blood rheology to disease detection, treatment, and prevention. This work aims to the development a robust and consistent hemorheological model, able to offer reliable predictions in variousrheometric tests such as shear or extensional flows. Additionally, it describes the blood flow in microtubes under steady and pulsatile conditions incorporating microcirculation phenomena such as the Fåhraeus and the Fåhraeus-Lindqvist effects. This work is extended to the overall study of microcirculation since blood flows into microvessels in which many mechanical and biochemical phenomena are involved, incorporating the interaction of the blood flow with the elastic walls. We introduce a fluid-structure interaction model in a coupled manner to provide accurate results of the vessel dilation and stress field under various intraluminal pressure conditions. We also account for smooth muscle contractility, an internal mechanism that incorporates biochemical phenomena which lead to the development of active stresses. Apart from the integrated modeling of blood rheological complexity, our implementation is adequate for multi-dimensional simulations due to its tensorial formalism. To this end, blood flow in 3D aneurysmal geometries is investigated under sinusoidal waveforms with different frequencies, amplitudes, and patterns, providing a thorough parametric study. This work offers accurate predictions of the instantaneous structure of blood as well as of WSS which are strongly correlated with aneurysm growth, stabilization, and rupture.