Finite element simulations of arterial blood flow serve to provide pressure, velocity pattern and wall shear stress in regions of arterial dilatations and bifurcations. Even moderate size models require solving linear systems with millions of unknowns; 15 - 20 hours per time step is an average sequential run time, therefore, parallel computing is a necessity.

We present a hybrid parallelization frame- work to solve large scale problems of hemo- dynamics using OpenMP in conjunction with MPI environment. We demonstrate that computational performance of a finite element code could be dramatically improved, when a proper use of a multi-core architecture is carried out. We use an open source FreeFem++ platform. A speed-up of x56 is measured for the IBM iDataPlex UPMC cluster with 96 cores.

MPI/OpenMP programming mode

FreeFem++ code

3.4 million unknowns model