ANALYSIS OF 3D TRANSIENT BLOOD-FLOW PASSING THROUGH AN ARTIFICIAL AORTIC-VALVE BY LATTICE-BOLTZMANN METHODS

The development of flow instabilities due to high Reynolds number flow in artificial heart valve geometries inducing high strain rates and s tresses often leads to hemolysis and related highly undesired effects. Geometric and functional optimization of artificial heart valves is t herefore mandatory. In addition to experimental work in this field it is meanwhile possible to obtain increasing insight into flow dynamics by computer simulation of refined model problems. After giving an intr oductory overview we report the results of the simulation of three-dim ensional transient physiological flows in fixed geometries similar to a CarboMedics bileaflet heart valve at different opening angles. The v isualization of emerging complicated flow patterns gives derailed info rmation about the transient history of the systems dynamical stability . Stress analysis indicates temporal sheer stress peaks even far away from walls. The mathematical approach used is the Lattice-Boltzmann me thod. We obtained reasonable results for velocity and shear stress fie lds. The code is implemented on parallel hardware in order to decrease computation time. Finally, we discuss problems, shortcomings and poss ible extensions of our approach. (C) 1998 Published by Elsevier Scienc e Ltd. All rights reserved.