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Title: Inflow/outflow boundary conditions for particle-based blood flow simulations: Application to arterial bifurcations and trees

When blood flows through a bifurcation, red blood cells (RBCs) travel into side branches at different hematocrit levels, and it is even possible that all RBCs enter into one branch only, leading to a complete separation of plasma and R- BCs. To quantify this phenomenon via particle-based mesoscopic simulations, we developed a general framework for open boundary conditions in multiphase flows that is effective even for high hematocrit levels. The inflow at the inlet is duplicated from a fully developed flow generated in a pilot simulation with periodic boundary conditions. The outflow is controlled by adaptive forces to maintain the flow rate and velocity gradient at fixed values, while the particles leaving the arteriole at the outlet are removed from the system. Upon valida- tion of this approach, we performed systematic 3D simulations to study plasma skimming in arterioles of diameters 20 to 32 microns. For a flow rate ratio 6:1 at the branches, we observed the \all-or-nothing" phenomenon with plasma only entering the low flow rate branch. We then simulated blood-plasma separation in arteriolar bifurcations with different bifurcation angles and same diameter of the daughter branches. Our simulations predict a significant increase in RBC flux through the main daughtermore » branch as the bifurcation angle is increased. Lastly, we demonstrated the new methodology for simulating blood flow in ves- sels with multiple inlets and outlets, constructed using an angiogenesis model.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [5]
  1. Univ. of Lugano, Lugano (Switzerland)
  2. Brown Univ., Providence, RI (United States)
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  4. Univ. of Lugano, Lugano (Switzerland); Swiss Institute of Bioinformatics, Lausanne (Switzerland)
  5. Univ. of British Columbia, Vancouver, BC (Canada)
Publication Date:
OSTI Identifier:
1229970
Report Number(s):
PNNL-SA--109087
Journal ID: ISSN 1553-7358; KJ0401000
Grant/Contract Number:
AC05-76RL01830
Type:
Accepted Manuscript
Journal Name:
PLoS Computational Biology (Online)
Additional Journal Information:
Journal Name: PLoS Computational Biology (Online); Journal Volume: 11; Journal Issue: 8; Journal ID: ISSN 1553-7358
Publisher:
Public Library of Science
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES blood flow; flow rate; fluid flow; blood plasma; simulation and modeling; hematocrit; blood; biophysical simulations