CFD 101: How Computational Fluid Dynamics (CFD) Can Help Us Understand Sleep-Disordered Breathing
- Daniel Grafton
- Sep 19, 2025
- 3 min read
Disclaimer: The information in this post is for educational purposes only. It is not a medical diagnosis or treatment and should not be used to make healthcare decisions. Always consult a licensed provider for medical advice.
What is CFD?
Computational Fluid Dynamics (CFD) is a simulation technique widely used in engineering to study how gases or liquids move and interact with their surroundings. Engineers apply it to understand the aerodynamics of cars, the lift of airplane wings, or how engines are cooled.
In recent years, researchers have also applied CFD to biology and medicine. When used to model airflow in the human upper airway, CFD provides a physics-based way to visualize how air moves through structures like the nose, pharynx, and larynx.
Why is CFD relevant to sleep and breathing research?
Sleep-disordered breathing (SDB) is linked to how air moves through the upper airway during sleep. Researchers studying airflow patterns often examine three variables:
Pressure – Negative pressure can draw airway walls inward, especially when passages are narrowed.
Velocity – Faster airflow through tight regions leads to lower pressure, which can influence airway stability.
Turbulence – Smooth airflow is efficient; turbulent airflow increases resistance and energy loss.
By simulating these dynamics, CFD generates quantitative, physics-based data on how airflow behaves within the airway. These data can be visualized to show how physical forces may interact with anatomy, giving researchers a tool to explore hypotheses about phenomena such as snoring, flow limitations, and other aspects of sleep-disordered breathing.
How are CFD simulations created?
Researchers typically start with 3D anatomical models of the airway derived from imaging (such as CT or MRI scans). Using specialized software, airflow can then be simulated under different conditions.
The output includes maps of pressure, velocity, turbulence, and airflow streamlines. These results don’t provide a diagnosis but can be valuable in exploring how anatomy and airflow interact.
Where does CFD fit in SDB research?
In published studies, CFD has been used as a research tool to generate data on airflow dynamics in the upper airway. Examples include:
Mapping areas where airflow resistance is higher under simulated conditions
Comparing airflow patterns before and after anatomical changes (e.g., surgical or orthodontic interventions studied in research settings)
Exploring how turbulence, velocity, and pressure interact with airway anatomy
These applications provide quantitative, physics-based insights that complement traditional research methods. While CFD does not serve as a diagnostic test on its own, it can help scientists and clinicians form hypotheses and better understand mechanisms involved in sleep-disordered breathing.
Why isn’t CFD routine today?
Currently, CFD is used mostly in academic research and some specialized centers. Barriers include:
Awareness – Many clinicians are not yet familiar with CFD outside research literature.
Complexity – High-quality simulations require specialized expertise.
Scope – CFD is a tool for visualization and hypothesis generation, not a standalone diagnostic.
That said, interest is growing. Some research groups and hospitals are experimenting with integrating CFD into studies of surgical planning and airway modeling.
The bigger picture
CFD should be seen as one piece of the puzzle. On its own it cannot diagnose or treat conditions, but alongside established tools like sleep studies, imaging, and clinical evaluation, it provides another lens through which to study breathing.
Looking forward, as technology improves, CFD may become easier to use in research and educational settings. Its role could expand as part of a broader effort to help patients and providers better understand sleep-disordered breathing. For an in-depth overview of the applications of CFD to SDB in research and potential clinical implications, please see our other post "CFD in Sleep-Disordered Breathing Research: Applications and Insights".
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