A novel pressure boundary condition based on homothety human factors

A new and novel pressure boundary condition is developed based on the homothety factors of the human airways. The mathematical model, which has the ability to calculate the pressure drop of a number N of airway generations, is validated through CFD simulations for different Reynolds numbers. The boundary condition is implemented in the open source OpenFOAM. Two application cases are developed: the first, a study of airways with an asthma condition using a synthetic model, and the second, a study of airways collapse using a real specific patient model. The results and validations shown a low relative error between the pressure drops obtained with the complete CFD models and the hybrid simulations using CFD with the new boundary condition.