Lattice Boltzmann simulation on particle suspensions in a two-dimensional symmetric stenotic artery

The technique of lattice Boltzmann simulation has been applied to the study of two-dimensional particle suspensions through a modeled arterial stenosis. The stenosis model consists of two-side symmetric semicirculars in a planar channel with the width of the stenosis throat larger than d and less than 2d, where d is the diameter of the particles. When only one particle is positioned off-centerline initially, the particle migrates off-centerline after passing the stenosis and the velocity at the stenosis throat is much larger than that in a flat tube. Only when two particles are positioned symmetrically to the centerline to a very high accuracy can the flow be blocked by two particles completely. A very small asymmetry will be amplified proximal to the stenosis throat in that one of the particles goes back to leave space to let the other particle passing the stenosis first so that the particles cannot be blocked. An evidence of attractive interactions between the particles as well as a particle and a proximal protuberance is observed when the asymmetry is very small and the width at the stenosis throat is between two critical values. The hematocrit distribution of the particles is studied by simulating multiparticle suspensions. It is found that the width of the stenosis throat has a significant influence on the hematocrit distribution of the particles in the flat tubes far from the stenosis.