Characterizing transition to turbulence in pulsatile flows
Pennsylvania State University
Abstract
Transition to turbulence in pulsatile flow has been observed across a variety of application areas including biomedical, environmental, and turbomachinery flows. Prior studies, in the biomedical domain for example, have (controversially) reported transitional flow behaviors to exist even in flows with mean Reynolds numbers as low as 250. The intermittent flow structures associated with the transitional regime cause significant fluctuations in flow parameters such as wall shear stress (WSS) and pressure. Quantifying these effects is important as these intermittent flow behaviors can weaken materials to failure, cause performance reductions, and lead to other adversarial effects. However, the mechanisms driving the onset and development of transitional flow remain poorly understood. In this talk, I will discuss the results of our experimental studies which parametrically evaluate how axial flow factors (e.g., changes to Womersley number, inflow waveform shape) affect the onset of transitional flow. Additionally, I will discuss our ongoing efforts to develop a universal metric to characterize the extent to which turbulence-scales exist in any arbitrary flow.
About the speaker
Dr. Melissa Brindise is an Assistant Professor in the Department of Mechanical Engineering at Penn State University. She received her B.S. in Aeronautical Engineering (2013) and Ph.D. in Mechanical Engineering (2019) both from Purdue University. Prior to joining Penn State in 2021, she was a post-doctoral research associate at Purdue as part of the Eli Lilly–Purdue partnership. Her research combines experimental flow physics with image and signal processing to improve analysis methods and current clinical understanding of neuro- and cardiovascular disease, injury, function, and treatment. Broadly, her lab focuses on 1) advancing our understanding of the role of hemodynamics and vascular changes in the onset, progression, and efficacy of treatment of diseases and 2) developing objective, evidence-based methods to transform how we interpret patient data. Her current research interests include the application areas of cerebral aneurysms, Moyamoya disease, cognitive function, heart disease and arrhythmias, and transition to turbulence in unsteady flows.
