Abstract
Cerebral aneurysms are bulges appearing on brain arteries. The development, growth and rupture has been intensively studied using numerical tools. We present a series of studies covering many of the open questions related to the boundary conditions used in numerical simulations, namely the inlet, outlet and the wall. The effect of boundary conditions cannot be overestimated; yet it received much less attention than it would have deserved.An analytical formula of the pulsating pipe flow with rigid walls is used to study the effects of the varying parameters of the cardiac cycle. Both idealised and real geometries are used to study the propagation of the boundary effects, and to analyse the effects of distensible boundaries.Our results provide useful criteria for the necessary inlet and outlet length. We found that the deformability of wall boundaries has a significant influence; however, simulations with rigid walls are still able to capture the main hemodynamic properties of the flow.The results can be effectively used in the simulation of cerebral aneurysm and provide a firmer ground in a broader sense for hemodynamic simulations.
Highlights
Aneurysms are dilated sections of blood vessels appearing at various locations of the cardiovascular system
3 Results 3.1 Inlet boundary condition 3.1.1 Analytical studies With the reconstruction of the Womersley profile the effect of various properties of the cardiac cycle on the flow was studied
The mean value of the flow rate is apparent in the Womersley formulae as the weight factor of its zeroth term (see Eq (2)), which is the parabolic part of the profile
Summary
Aneurysms are dilated sections of blood vessels appearing at various locations of the cardiovascular system. The flow inside vessels are usually assumed to be laminar, blood is treated as an incompressible, Newtonian liquid With these assumptions advanced numerical solvers are able to calculate the flow accurately. Cebral et al [3] found the calculated flow to be insensitive to slight geometrical variations They compared results based on models derived from the same medical images by different persons. Advanced mesh generation codes that are part of numerical simulation packages are able to generate high quality meshes These include the appropriate resolution near the vessel wall, which can be efficiently assured using prismatic elements. The effect of these grids on numerical accuracy can be well monitored with the help of mesh studies
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
