Patient-specific optimisation of inhaled drug delivery
Geometric variation of the respiratory airways across subjects has a pronounced effect on the flow dynamics and aerosol deposition, motivating personalised treatment of respiratory diseases. Towards this goal, we have developed unique patient- specific modelling capabilities for flow and particle deposition in the respiratory airways.
Characterisation of aerosol transport and deposition
Prediction of aerosol deposition in the respiratory system is important for improving the efficiency of inhaled drug delivery and for assessing the toxicity of airborne pollutants. Particle deposition in the airways is typically described as a function of the Stokes number based on a reference flow timescale. This choice leads to significant scatter in deposition data since the velocity and length scales experienced by the particles as they are advected through the flow deviate considerably from the reference values in many sections of the airways.
Numerical methods for complex geometries
Immersed boundary (IB) methods have become an established approach for modelling complex and moving geometries. The main advantage and the popularity of these methods are due to their simplicity and efficiency. Unlike body-conforming methods which require a body-fitted grid and remeshing in moving boundary problems, a structured grid is adopted for the IB method. This greatly simplifies the task of grid generation, particularly for moving bodies, and leads to more efficient computational algorithms with better convergence and stability properties.
Flow and aerosol deposition in the alveoli
Computational fluid dynamics (CFD) simulations provide an effective approach for examining the fluid flow and aerosol transport in the respiratory airways. However, while there have been numerous numerical studies of aerosol transport in the conducting airways, few have focused on the alveolar region of the lung. Furthermore, the studies to date have adopted rigid-walled alveolar duct structures and simplified geometrical models.