A unified method for estimating pressure losses at vascular junctions.

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Computational Modeling

Background:

• Reduced-order (0D/1D) models often neglect junctional pressure losses in physiological flow simulations.
• Existing empirical methods for estimating these losses are geometry-specific and can cause discontinuities in pulsatile flow simulations.

Purpose of the Study:

• To develop a unified method (Unified0D) for estimating pressure loss coefficients at any junction geometry and flow regime.
• To ensure smooth transitions in simulated haemodynamic waveforms during pulsatile, multi-directional flows.

Main Methods:

• Extended Bassett et al.'s control volume method with a 'pseudodatum' supplier branch.
• Incorporated empirical methods to account for energy exchange between diverging flow streams.
• Validated the Unified0D formulation using high-resolution computational fluid dynamics.

Main Results:

• The Unified0D method accurately estimates loss coefficients across various flow conditions and junction configurations.
• High-resolution CFD validation confirmed the formulation's efficacy.
• A 1D simulation demonstrated smooth transitions in calculated pressure losses, even with regime changes.

Conclusions:

• The Unified0D method provides a robust and versatile approach for modeling junctional pressure losses in reduced-order physiological flow models.
• This unified method enhances the accuracy and realism of haemodynamic waveform simulations, particularly in complex flow scenarios.