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A relationship between Reynolds stresses and viscous dissipation: implications to red cell damage
1Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA.
Annals of Biomedical Engineering
|January 1, 1995
Summary
Turbulent flows can damage red blood cells through viscous shearing. This study suggests viscous dissipation is a key indicator of cellular damage, aligning with red blood cell size and shear stress thresholds.
Area of Science:
- Biophysics
- Fluid Mechanics
- Cell Biology
Background:
- Turbulent flows can cause cellular damage, particularly to erythrocytes (red blood cells).
- Understanding the mechanisms of turbulent hemolysis is crucial for various biomedical applications, including blood-contacting devices.
Purpose of the Study:
- To examine viscous shearing as a mechanism for turbulent flow-induced cellular damage.
- To evaluate Reynolds stress and propose viscous dissipation as a measure of hemolysis.
- To compare shear stress thresholds and length scales in turbulent and laminar flow studies.
Main Methods:
- Analysis of existing literature data on turbulent hemolysis.
- Relating Reynolds stresses to viscous dissipation under simple flow conditions.
- Comparison of Kolmogorov length scales with red blood cell size.
Main Results:
- Viscous shearing is identified as a significant mechanism in turbulent erythrocyte destruction.
- Instantaneous viscous shear stress at hemolysis correlates with laminar flow thresholds.
- Kolmogorov length scales in turbulent hemolysis studies are comparable to red blood cell dimensions.
Conclusions:
- Viscous shearing is a primary cause of red blood cell damage in turbulent flows (jet and Couette).
- Viscous dissipation serves as a relevant indicator for turbulent hemolysis.
- Pressure fluctuations may also contribute to cellular damage, especially for larger cells.