Last summer, I received a request to produce a competition entry for the Gallery of Fluid Motion of the APS Division of Fluid Dynamics. The entry would involve depicting the vortex structures and transition to turbulence behind biological heart valves. It’s a pretty complex topic for a layperson like me, but I was intrigued and started googling.
The request came from a doctoral candidate from the Cardiovascular Engineering Group at the ARTORG Center in Bern. Karoline Bornemann works on numerical simulations of the interaction between biological heart valve prostheses and the surrounding blood flow. The Gallery of Fluid Motion is an international competition aimed at visually and appealingly presenting fluid mechanics problems in the form of a three-minute video.
My first task was to overcome the initial lack of knowledge that led to a steep learning curve. Then I watched comparative videos on the Gallery of Fluid Motions website. To make it easier to get into the video, I drew a stop-motion animation of a heart to show what it was all about: the human heart.
After several months of work, numerous drafts, and meetings, the final product emerged with the title: «Transition to Turbulence Past Bioprosthetic Aortic Valves». Aortic valve replacement with a valve prosthesis is necessary when the native valve is compromised. During the ejection phase of the heart, bioprosthetic aortic valves create turbulent flow which is suspected to negatively affect the valve’s durability and performance. Depending on their design, the valve leaflets may exhibit periodic oscillations – so-called leaflet fluttering – making this a complex fluid-structure interaction problem.This video shows visualizations of the vortex development and breakdown past a fluttering and non-fluttering valve and demonstrates the effect of leaflet fluttering on laminar-turbulent transition.
The project was submitted to the «Gallery of Fluid Motion» presented by the APS Division of Fluid Dynamics in early September. In November, I received the great news from Karoline that the video had been selected as the winner of the 2024 APS/DFD Gallery of Fluid Motion Award.
