An overview of numerical modelling of nasal airflow.

Computer modelling of fluid flows is a mature technology used widely in engineering. The process, known as computational fluid dynamics (CFD), allows accurate prediction of fluid flow and associated phenomena based on the mathematical laws governing fluid behaviour. A fluid may be defined as any substance that can flow and thus both liquids and gases behave as fluids. The mathematical predictions of CFD can therefore be applied to nasal airflow. In current clinical practice, it is only possible to perform a few limited measurements of nasal airflow, and the clinical relevance of these measurements is questionable. Computer models are not limited by the anatomical inaccessibility of the nasal cavities, and a detailed objective characterisation of airflow can therefore be provided in all areas of an individual nose. In addition, the ability to remodel computer simulations offers a potential predictive tool for planning nasal surgery. This article provides an overview of the basic concepts of computational fluid dynamics, and a summary of the current capabilities of this technology in the characterisation of nasal airflow. The objective is to give otorhinolaryngologists a basic understanding of the computer modelling of nasal airflow, and the background information with which to evaluate CFD-based rhinology literature.