This dissertation, "The Applications of Computational Fluid Dynamics to the Cardiovascular System and the Respiratory System" by Yi, Fan, 樊怡, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: The diseases of cardiovascular system and the respiratory system have been the second and third killers causing deaths in Hong Kong. In this stressful civilized world, the prevalence and incidence of these diseases increased prominently which arouse our concern on the theories behind the pathological conditions. This report will focus on the biofluid mechanics in the large artery and in the upper airway. Thoracic aortic dissection, characterized by the tearing in the middle layer of vessel wall, is a catastrophic vascular disorder. The wall of the newly formed channel, the false lumen, is weakened and prone to aortic events. Endovascular repair is a minimally invasive technique for treating dissection patients. The biomechanical factors and the length of endograft were studied by computational fluid dynamics. Two geometrical factors showed a significant impact on the backflow in the false lumen. A larger false lumen and a larger distal tear size greatly affected the extent of thrombosis in the false lumen. It made the false lumen under a higher risk of vessel rupture. The computational prediction also demonstrated a more stable hemodynamic condition in the model with a longer endograft. These results provide important information for the clinicians to propose the surgical procedures and to improve the design of endografts. Airway obstruction is a common breathing disorder but it is always underdiagnosed. Obstructive sleep apnea (OSA) and different dentofacial deformities are two pathological conditions in which the patients have the abnormal sizes of airways. Computational fluid dynamic was employed in both conditions with patient-specific models. In the part of OSA, pre- and post-operative models were studied. The dimensions and flow resistance of the upper airway showed a significant improvement after mandibular distraction. The percentage of stenosis and the flow resistance was reduced by 27.3% and 40.7% respectively. For the patients in three facial skeletal deformity groups, the cross-sectional area and the flow resistance were compared. The patients with Class II deformity had the smallest retroglossal and retroplatal dimensions as well as the greatest flow resistance. The results confirmed the effectiveness of mandibular distraction and also provide valuable implications for the clinicians on the treatment planning, particularly for the Class II subjects. DOI: 10.5353/th_b4775319 Subjects: Fluid dynamics - Mathematical models Cardiovascular system - Mechanical properties Respiratory system - Mechanical properties

Traditional research methodologies in the human respiratory system have always been challenging due to their invasive nature. Recent advances in medical imaging and computational fluid dynamics (CFD) have accelerated this research. This book compiles and details recent advances in the modelling of the respiratory system for researchers, engineers, scientists, and health practitioners. It breaks down the complexities of this field and provides both students and scientists with an introduction and starting point to the physiology of the respiratory system, fluid dynamics and advanced CFD modeling tools. In addition to a brief introduction to the physics of the respiratory system and an overview of computational methods, the book contains best-practice guidelines for establishing high-quality computational models and simulations. Inspiration for new simulations can be gained through innovative case studies as well as hands-on practice using pre-made computational code. Last but not least, students and researchers are presented the latest biomedical research activities, and the computational visualizations will enhance their understanding of physiological functions of the respiratory system.

This book discusses geometric and mathematical models that can be used to study fluid and structural mechanics in the cardiovascular system. Where traditional research methodologies in the human cardiovascular system are challenging due to its invasive nature, several recent advances in medical imaging and computational fluid and solid mechanics modelling now provide new and exciting research opportunities. This emerging field of study is multi-disciplinary, involving numerical methods, computational science, fluid and structural mechanics, and biomedical engineering. Certainly any new student or researcher in this field may feel overwhelmed by the wide range of disciplines that need to be understood. This unique book is one of the first to bring together knowledge from multiple disciplines, providing a starting point to each of the individual disciplines involved, attempting to ease the steep learning curve. This book presents elementary knowledge on the physiology of the cardiovascular system; basic knowledge and techniques on reconstructing geometric models from medical imaging; mathematics that describe fluid and structural mechanics, and corresponding numerical/computational methods to solve its equations and problems. Many practical examples and case studies are presented to reinforce best practice guidelines for setting high quality computational models and simulations. These examples contain a large number of images for visualization, to explain cardiovascular physiological functions and disease. The reader is then exposed to some of the latest research activities through a summary of breakthrough research models, findings, and techniques. The book’s approach is aimed at students and researchers entering this field from engineering, applied mathematics, biotechnology or medicine, wishing to engage in this emerging and exciting field of computational hemodynamics modelling.

Cardiovascular and Respiratory Systems: Modeling, Analysis, and Control uses a principle-based modeling approach and analysis of feedback control regulation to elucidate the physiological relationships. Models are arranged around specific questions or conditions, such as exercise or sleep transition, and are generally based on physiological mechanisms rather than on formal descriptions of input-output behavior. The authors ask open questions relevant to medical and clinical applications and clarify underlying themes of physiological control organization. Current problems, key issues, developing trends, and unresolved questions are highlighted. Researchers and graduate students in mathematical biology and biomedical engineering will find this book useful. It will also appeal to researchers in the physiological and life sciences who are interested in mathematical modeling.

This book covers emerging areas in novel design and their hydrodynamic properties relevant to bioreactors, environmental system, electrochemical systems, food processing and biomedical engineering. This book uses an interdisciplinary approach to provide a comprehensive prospective simulation modeling and hydrodynamic study in advanced biotechnological process and includes reviews of the most recent state of art in modeling and simulation of flows in biological process, such as CFD. Written by internationally recognized researchers in the field, each chapter provides a strong introductory section that is useful to both readers currently in the field and readers interested in learning more about these areas.