Outflow boundary conditions for arterial networks with multiple outlets

Area of Science:

• Computational fluid dynamics
• Biomedical engineering
• Cardiovascular research

Background:

• Simulating blood flow in complex arterial networks requires accurate, robust, and easily implementable boundary conditions for parallel computing.
• Existing methods like Resistance or Windkessel boundary conditions offer approximations, but incorporating clinically measured flow rates directly is often preferred for accuracy.

Purpose of the Study:

• To develop and validate a new numerical method for incorporating measured flow rates at multiple outlets in arterial network simulations.
• To ensure the method is computationally efficient and comparable to existing boundary conditions.

Main Methods:

• A novel boundary condition was developed, combining a time-dependent resistance condition for pressure with a Neumann condition for velocity at multiple outlets.
• The method was implemented within a parallel computing framework for large-scale simulations.
• Numerical convergence for specified outlet flow rates was assessed.

Main Results:

• The new method achieved fast convergence for numerical solutions with specified outlet flow rates.
• Computational complexity was comparable to established Resistance and Windkessel boundary conditions.
• Validation was successfully performed on a patient-specific cranial vascular network with 20 arteries and 10 outlets.

Conclusions:

• The developed method provides an accurate and efficient way to incorporate measured flow rates into complex arterial network simulations.
• This technique offers a significant advancement for physiologically accurate blood flow modeling, particularly in patient-specific vascular networks.