Bjbm Berent Wolters

Finite-element-based computational methods for cardiovascular fluid-structure interaction

In this paper a combined arbitrary Lagrange-Euler fictitious domain (ALE-FD) method for fluid-structure interaction problems in cardiovascular biomechanics is derived in terms of a weighted residual finite-element formulation. For both fluid flow of blood and solid mechanics of vascular tissue, the performance of tetrahedral and hexahedral Crouzeix-Raviart elements are evaluated. Comparable convergence results are found, although for the test cases considered the hexahedral elements are more accurate. The possibilities that are offered by the ALE-FD method are illustrated by means of a simulation of valve dynamics in a simplified left ventricular flow model.

On the numerical analysis of coronary artery wall shear stress

A numerical analysis is performed in order to study coronary artery wall shear stress (WSS) and its dependence on (i) unsteadiness of the flow, (ii) motion and deformation of the blood vessel geometry and (iii) the shear thinning properties of blood. A non-stationary geometric model of the right coronary artery is developed from intravascular ultrasound measurements complemented with the 3D reconstructed measurement location and orientation. The velocity distribution in the model is computed by solving the arbitrary Lagrangian-Eulerian (ALE) formulation of the Navier-Stokes equations using a finite-element method. The averaged WSS pattern corresponding to time-dependent shear thinning flow in the non-stationary model is compared to the pattern corresponding to steady mean Newtonian flow in the rigid end-diastolic model.