A fast approach to determine resistances and compliances of the Windkessel models in the simulation of aortic flow

Getting the dynamics of blood flow in the aorta by computational fluid dynamics (CFD) provides a comprehensive picture of cardiovascular diseases, especially when clinical imaging techniques cannot reach some of the important measurements. A set of outlet boundary conditions (BCs) for downstream branches should be chosen with care to get an accurate simulation. In recent decades, the Windkessel model is widely used to be coupled with CFD to get more realistic pressure waveforms and flowrate distributions. In this work, we will demonstrate an algorithm to get the appropriate resistance and compliance of each outlet with the consideration of flow resistances from the geometry, and coupled with lattice Boltzmann method to obtain patient-specific flow patterns in the aorta. The whole procedure is automated and very fast to achieve prescribed flow distributions and max and min pressures at each branch with only one extra simulation of steady flow at peak systole. The mean L2 norm errors of CFD results compared to prescribed values are for flowrate distribution – 0.24%, for pressure – 4.82 mmHg.