SCHOOL OF MECHANICAL ENGINEERING SEMINAR Thursday, March 22, 2012 at 14:00 Wolfson Building of Mechanical Engineering, Room 234

Large Eddy Simulation of Powered Fontan Hemodynamics

Prof. Steven H. Frankel

School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA

Modeling and simulation of cardiovascular medical devices are challenging due to the presence of three-dimensional unsteady, transitional and possibly turbulent flow, rotating machinery, and complex vessel geometries. The majority of computational biofluid dynamic studies reported in the literature employ commercial CFD codes featuring low order numerical methods and standard RANS-based turbulence models. In this study, large eddy simulations (LES) of the three-dimensional unsteady flow in an idealized total cavopulmonary connection are conducted. The effect of including a novel mechanical assist device, called a viscous impeller pump, at the center of the vessel junction is also studied. The in-house parallel computer code integrates the incompressible Navier-Stokes equations on a staggered Cartesian structured grid using a high-order finite-difference method, a global-coefficient subgrid-scale eddy viscosity model, and an immersed boundary method. Validation cases include flow over a sphere as well as model stenotic flow featuring comparisons to a direct numerical simulation database. Predictions from LES of powered Fontan hemodynamics are compared to both steady and unsteady RANS results, and more importantly to experimentally velocity data obtained from particle imaging velocimetry measurements and novel flow features are analyzed.

Fundamental Physics of Polymer-Turbulence Interactions underlying Drag Reduction, from Homogeneous Shear Flow DNS with the FENE-P Model

Prof. James G. Brasseur