Abstract
The lattice Boltzmann method (LBM) is a popular alternative to solving the Navier-Stokes equations for modeling blood flow. When simulating flow using the LBM, several choices for inlet and outlet boundary conditions exist. While boundary conditions in the LBM have been evaluated in idealized geometries, there have been no extensive comparisons in image-derived vasculature, where the geometries are highly complex. In this study, the Zou-He (ZH) and finite difference (FD) boundary conditions were evaluated in image-derived vascular geometries by comparing their stability, accuracy, and run times. The boundary conditions were compared in four arteries: a coarctation of the aorta, dissected aorta, femoral artery, and left coronary artery. The FD boundary condition was more stable than ZH in all four geometries. In general, simulations using the ZH and FD method showed similar convergence rates within each geometry. However, the ZH method proved to be slightly more accurate compared with experimental flow using three-dimensional printed vasculature. The total run times necessary for simulations using the ZH boundary condition were significantly higher as the ZH method required a larger relaxation time, grid resolution, and number of time steps for a simulation representing the same physiological time. Finally, a new inlet velocity profile algorithm is presented for complex inlet geometries. Overall, results indicated that the FD method should generally be used for large-scale blood flow simulations in image-derived vasculature geometries. This study can serve as a guide to researchers interested in using the LBM to simulate blood flow.
| Original language | English |
|---|---|
| Article number | e3198 |
| Journal | International Journal for Numerical Methods in Biomedical Engineering |
| Volume | 35 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 2019 |
Funding
This work was performed under the auspices of the US Department of Energy by LLNL under contract DE-AC52-07NA27344. Computing support for this work came from the LLNL Institutional Computing 305 Grand Challenge program. Support was also provided by the LLNL Laboratory Directed Research and Development (LDRD) program. Research reported in this publication was supported by the Office of the Director, National Institutes Of Health under award number DP5OD019876. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Support was provided by the Big Data-Scientist Training Enhancement Program (BD-STEP) of the Department of Veterans Affairs, the Hartwell Foundation, Duke Morton H. Friedman and Duke Theo Pilkington Fellowship. We thank Duke OIT for their help with the Duke Compute Cluster runs. We also thank Luiz Hegele and Ismael Perez for their careful review and feedback on this work.
Keywords
- Zou-He
- boundary conditions
- finite difference
- hemodynamics
- image-derived vasculature
- lattice Boltzmann method