On Eulerian versus Lagrangian models of mechanical blood damage and the linearized damage function

Area of Science:

• Biomedical Engineering
• Fluid Dynamics
• Computational Mechanics

Background:

• Hemolysis prediction is crucial for evaluating blood damage in medical devices.
• The Eulerian method offers a computational approach to predict hemolysis.
• Previous models often rely on linearized blood damage functions.

Purpose of the Study:

• To identify and address limitations in the Eulerian method for hemolysis prediction.
• To evaluate the impact of linearization on the accuracy of hemolysis prediction.
• To explore the applicability of the Eulerian method in complex flow scenarios.

Main Methods:

• Analysis of the Eulerian method's derivation from a Lagrangian power-law model.
• Investigation of the spatial dependence of exposure duration in fluid stress.
• Examination of the validity constraints of linearization for blood damage functions.

Main Results:

• The Eulerian method, as derived, neglects spatial variations in exposure duration, limiting its validity to steady, uniaxial flow.
• Linearization of the blood damage function imposes constraints that severely restrict the method's applicability.
• The source term in the Eulerian method does not account for velocity differences in similar flows, necessitating complex flow field analysis for accurate correction.

Conclusions:

• The current Eulerian method for hemolysis prediction has significant limitations due to simplifications in its derivation.
• Accurate application of the Eulerian method to complex flows, such as those in cardiovascular devices, requires overcoming these limitations.
• Further development is needed to enhance the robustness and applicability of Eulerian hemolysis prediction models.