When
Where
Student: Dunia Fernandez, Program in Applied Mathematics
Title: Fluid Dynamics of Valveless Pumping in Tubular Hearts
Advisor: Laura Miller, Dept of Mathematics
Location: Math building, Room 401
Abstract: The vertebrate embryonic heart first develops as a simple valveless tube, yet its pumping mechanism remains debated, with theories ranging from peristaltic pumping to dynamic suction pumping (DSP), or a hybrid of both. This dissertation uses immersed boundary simulations to investigate how geometry, actuation, and dimensionless parameters relevant to cardiac morphogenesis drive circulation in these tiny hearts. I develop a novel two-point DSP model inspired by dual pacemaker activity in ascidians, extend the framework into three dimensions to capture more realistic deformation and flow, and examine peristaltic pumping in a heart tube confined by a pericardium. Results reveal that pumping performance depends strongly on Womersley number, phase lag between contractions, elasticity, and geometric confinement. The 3D DSP model uncovers flow regimes absent in 2D, and pericardial confinement is shown to regulate flow amplitude without altering waveform. Together, these findings demonstrate how mechanical and structural features affect fluid flow efficiency in valveless embryonic hearts, offering new insights into cardiac morphogenesis, valveless pumping, and fluid transport at the earliest stages of vertebrate heart development.