MechE Seminar Series

From Lab to Clinic: Advancing Flow Velocity Measurements in Fluid Mechanics and Cardiovascular Flow Imaging

Flow velocity measurements underpin our understanding of flow physics in research laboratories and clinical environments. Accurate quantification of these measurements is essential for studying fundamental flow phenomena. In the first part of this seminar, I will discuss progress in uncertainty quantification methods for particle image velocimetry (PIV). These methods leverage robust statistical models and advanced signal processing to address the inherent challenges of velocity measurement in complex and dynamic flows, thereby improving accuracy and reliability in experimental fluid mechanics.

In the second part, I will highlight how these principles extend to medical imaging modalities such as ultrasound and phase-contrast MRI. The human cardiovascular system exhibits intricate flow patterns that significantly deviate in disease states; accurately measuring these flows is key to diagnosing and monitoring conditions like congenital heart defects, aneurysms, and heart failure. However, inherent limitations such as image noise, resolution constraints, and velocity reconstruction errors present significant obstacles. This presentation will explore new techniques that enhance cardiovascular flow measurements, including data augmentation guided by flow physics, phase unwrapping, denoising approaches, and advanced bias error modeling. I will also demonstrate how refined methods for measuring parameters such as relative pressure, wall shear stress, and other flow-derived markers can be integrated to improve accuracy and resolution. Illustrative examples from preclinical and clinical studies will showcase how these tools help connect flow characteristics (e.g., pressure, shear, strain, and energy losses) to disease conditions—ultimately fostering improved diagnosis, treatment, and patient outcomes.

Pavlos P. Vlachos, Purdue University

Dr. Pavlos Vlachos is a professor at the School of Mechanical Engineering and the Weldon School of Biomedical Engineering (by courtesy) at Purdue University. He serves as the St. Vincent Health Professor of Healthcare Engineering. He is Director of the Regenstrief Center for Healthcare Engineering and the Eli Lilly and Purdue University Research Alliance Center.

He received his Diploma in Mechanical Engineering from the National Technical University of Athens (1995) and his M.S. (1998) and Ph.D. (2000) in Engineering Science and Mechanics from Virginia Tech. After serving as a visiting and then research assistant professor at Virginia Tech, he joined the Department of Mechanical Engineering there as an assistant professor in 2003, was promoted to associate professor with tenure in 2007, and became a full professor in 2011. He joined Purdue University in 2013.

Dr. Vlachos’s research focuses on biofluids and biomechanics, with applications in cardiovascular disease, drug delivery, congenital heart defects, cerebral aneurysms, and diagnostics using ultrasound and MRI. He also studies tissue biotransport and nanoparticle-based therapies for drug delivery.

He has led or contributed to over 90 funded research projects (over $100M) and authored 197 journal articles and over 330 conference papers and abstracts. He has advised 12 postdocs, 25 Ph.D. dissertations, 30 M.S. theses, and has 12 patents (5 licensed) with 51 additional intellectual property disclosures.

Dr. Vlachos has earned numerous distinctions from prestigious organizations and academic bodies throughout his career. In 2020, he was named a Fellow of the American Society of Mechanical Engineers, followed by his election as a Fellow of the American Institute of Medical and Biological Engineers in 2022. He became a Fellow of the American Heart Association in 2023 and was recognized as a Fellow of the American Physical Society in 2024. Among other accolades, Dr. Vlachos counts the NSF CAREER Award and the MIT T.F. Ogilvie Lectureship Award, reflecting his continual pursuit of pioneering work in fluid mechanics and biofluids. He has also received multiple paper awards from societies and journals and various college-wide honors for outstanding research and teaching excellence.