Application of the lattice Boltzmann method to flow in aneurysm with ring-shaped stent obstacles

To resolve the characteristics of a highly complex flow, a lattice Boltzmann method with an extrapolation boundary technique was used in aneurysms with and without transverse objects on the upper wall, and results were compared with the non-stented aneurysm. The extrapolation boundary concept allows the use of Cartesian grids even when the boundaries do not conform to Cartesian coordinates. To ease the code development and facilitate the incorporation of new physics, a new scientific programming strategy based on object-oriented concepts was developed. The reduced flow, smaller vorticity magnitude and wall shear stress, and smaller du/dy near the dome of the aneurysm were observed when the proposed stent obstacles were used. The height of the stent obstacles was more effective to reduce the vorticity near the dome of the aneurysm than the width of the stent. The rectangular stent with 20% height-of-vessel radius was observed to be optimal and decreased the magnitude of the vorticity by 21% near the dome of the aneurysm.