A new three-dimensional computer model is offering scientists a closer look at one of the most familiar—and frustrating—sounds in human sleep: the rumble of ordinary snoring. Researchers at the KTH Royal Institute of Technology in Sweden have simulated how air moves through the upper airway, how soft tissues respond to that airflow, and how their motion can generate sound. Their study, published in Physics of Fluids, focuses on non-apneic snoring, the kind that occurs without the repeated breathing interruptions associated with obstructive sleep apnea. Although ordinary snoring is often treated as a nuisance rather than a medical problem, it can severely disrupt sleep for both the person making the sound and anyone nearby. The new model could help explain why some snoring becomes exceptionally loud and may eventually guide more precise interventions.
Snoring occurs when tissues in the upper airway vibrate as air passes through a partially narrowed passage during sleep. Yet the exact chain of events that converts breathing into a powerful acoustic signal remains difficult to characterize. The airway is not a rigid pipe: its shape changes, airflow is irregular, and the soft palate and surrounding structures can deform and oscillate. These factors interact in real time, making it challenging to determine whether the primary driver of a particular sound is the tissue motion, the airflow, or the aerodynamic forces connecting the two. Many previous studies have simplified one or more of these elements, for example by assuming steady breathing or treating airway tissues as stationary. According to the researchers, such simplifications can obscure the mechanisms responsible for palatal snoring.
The KTH team addressed the problem by building a computational representation of the upper airway that combines three key components: air movement, flexible soft tissue, and sound production. The model recreates airflow through the mouth and around the soft palate, a movable structure located behind the hard palate at the roof of the mouth. Unlike the hard palate, which has a firm, bony surface, the soft palate is composed of tissues capable of bending and vibrating. During sleep, changes in muscle tone can make these tissues more susceptible to aerodynamic forces. The simulation tracks how air accelerates and becomes unstable as it passes over the soft palate, while simultaneously calculating how the tissue responds. This type of fluid-structure interaction analysis is technically demanding because airflow and tissue motion continuously influence one another rather than occurring as separate processes.
The researchers found that the strongest simulated sounds were associated with unsteady airflow crossing the soft tissues of the mouth. Instead of a smooth, uniform stream, the air developed fluctuating patterns that exerted changing forces on the soft palate. Those forces encouraged the tissue to vibrate, and the vibration in turn altered the airflow, creating a feedback loop capable of producing an audible acoustic source. In physical terms, the sound is not generated simply because air passes through a narrow airway. It emerges from the interaction between unstable aerodynamic loading and the dynamic response of flexible tissue. The result suggests that the soft palate may act as a central sound-producing structure in at least some forms of non-apneic snoring, particularly when its movement becomes large enough to disturb the surrounding flow.
The model also helps distinguish the mechanical origins of snoring from the clinical features of sleep apnea. Sleep apnea involves repeated episodes in which the airway becomes obstructed or breathing stops, and it can reduce blood oxygen levels and place significant stress on the cardiovascular system. Snoring can accompany apnea, but it can also occur independently. The present work does not diagnose sleep apnea or replace clinical evaluation, and it does not claim that every case of snoring is caused by the same mechanism. Instead, it isolates a specific aerodynamic and tissue-motion pathway that may account for palatal non-apneic snoring. By focusing on the sound-generation process itself, the researchers hope to provide a physical basis for understanding why some people produce loud snoring even when they do not have the breathing interruptions characteristic of apnea.
The findings could eventually influence approaches designed to reduce palatal vibration. If unstable airflow and excessive soft-palate motion are major contributors to the sound, then treatments might aim to modify either the tissue mechanics or the airflow pattern. One possibility is palatal stiffening, a category of intervention intended to make the soft palate less flexible and therefore less likely to oscillate under aerodynamic forces. Another could involve altering the geometry of the airway or reducing the conditions that create unsteady flow. The study does not establish that any particular procedure will work, nor does it provide a clinical prescription. Instead, it identifies measurable physical targets: vibration amplitude, airflow behavior, dominant sound frequency, and the strength of the acoustic source. These variables could help researchers compare existing treatments or design new strategies based on how they change the underlying mechanics.
The researchers emphasize that the current simulation remains simplified. Human upper airways vary substantially in anatomy, and real snoring can involve multiple structures, including the soft palate, uvula, tongue, throat walls, and nasal passages. Sleep also changes muscle activity, body position, airway pressure, and tissue properties, all of which can influence the final sound. In addition, a computer model must make assumptions about material stiffness, tissue damping, airway geometry, and breathing conditions. Those assumptions allow the equations to be solved but can limit how directly the results apply to an individual sleeper. The model is therefore best understood as a controlled laboratory for testing physical mechanisms rather than as a finished tool for predicting a patient’s snoring or selecting a treatment.
The next phase of the project will examine how changing soft-palate stiffness affects the entire sound-generation process. By systematically varying the simulated tissue properties, the team plans to measure how stiffness influences the size and timing of tissue oscillations, the dominant frequency of the resulting sound, the organization of airflow, and the strength of the acoustic signal. Such analysis could clarify why stiffening procedures may reduce vibration in some circumstances and could reveal mechanical conditions under which snoring becomes quieter. More broadly, the work illustrates how computational fluid dynamics and biomechanics can be combined to investigate everyday health problems that are difficult to observe directly. A better understanding of the physics behind snoring may ultimately move anti-snoring research away from one-size-fits-all products and toward interventions matched to the specific airflow and tissue mechanics producing the sound.
Subject of Research: The airflow, soft-tissue vibration, and acoustic mechanisms responsible for non-apneic palatal snoring.
Article Title: Computational analysis of palatal non-apneic snoring sound generation using a simplified human upper airway model
News Publication Date: 18 August 2026
Web References: https://doi.org/10.1063/5.0346307; https://pubs.aip.org/aip/pof
References: Peng Li, Marco Laudato, and Mihai Mihaescu, Physics of Fluids, DOI: 10.1063/5.0346307
Image Credits: Li et al. (graph); Mussi Katz via Flickr, licensed under CC0 (photograph)
Keywords: Snoring, non-apneic snoring, soft palate, airflow, fluid-structure interaction, acoustics, upper airway, sleep disorders, computational modeling, fluid dynamics, palatal vibration, Physics of Fluids
