« Challenges and opportunities in computational hemodynamics »
by Franck Nicoud, Montpellier II University
Because many cardiovascular diseases are related to blood flow features, being able to predict how blood flows would open a window towards better diagnostic and treatment capabilities. To this respect, CFD is a natural complement to advanced medical imaging techniques which suffer from a lack of spatial resolution and cannot measure the stresses induced by the flow (pressure, wall shear stress). Still, several aspects make computational hemodynamics very challenging. Under in vivo conditions, blood usually interacts with thin deformable membranes or vessels in a time varying domain where boundary conditions and physical parameters are mostly uncertain. When blood flows in biomedical devices with manufactured surfaces (e.g. artificial valves or heart), biochemistry is often at play and leads to the formation of thrombus. Using CFD to optimize biomedical devices requires to be able to model and predict this phenomenon which must be avoided to keep the risk of embolism under control. Eventually, as a dense suspension of deformable red blood cells, blood is an extremely complex fluid whose rheology is essentially unknown except for its well-known shear-thinning behaviour. Several phenomena in micro-circulation which lead to hematocrit (and thus effective viscosity) heterogeneities are not understood yet. Being able to compute explicitly the motion-deformation-interaction of a large number of red blood cells would open new perspectives in terms of microcirculation understanding (in vivo) and management (in vitro). The developments made at University of Montpellier towards a reliable solver for macro and micro hemodynamics will be discussed in this talk together with some recent applications.