A three dimensional inSILICOmodel for the simulation of inspiratory and expiratory airflow in humans

Abstract

A three-dimensional, computational fluid dynamics model of the human respiratory system is put forward for consideration. This in silico model is based on existing state-of-the-art geometric approximations. As a complete simulation of the geometry would have unaffordable high computational costs, the model is composed of a single path of air from the mouth to the 16th bronchial generation, truncating the symmetrical branches that were not included. The innovation housed in this model is the development of a function that is applied to the truncated branches, which contemplates the behavior of the airflow within those branches, by copying cell by cell the velocity vectors existing in the symmetrical face of the developed branch. This model can reproduce the complete airflow process: inspiration and expiration cycles, through simulation in unsteady flow conditions. In normal breathing the air velocity varies within a narrow range, with steady changes. Therefore the model has been validated simulating a spirometry maneuver, in which an inspiration and expiration are performed in the most demanding conditions in order to obtain a wide speed range with faster variations.

An Overview of Experiments and Numerical Simulations on Airflow and Aerosols Deposition in Human Airways and the Role of Bioaerosol Motion in COVID-19 Transmission

“…After truncation, appropriate boundary conditions are imposed on the truncated sections by applying prior pressure conditions or stochastically coupled boundary conditions. A truncated model was used by Tena et al (2015) whereby the same velocity vector fields were imposed on the truncated sections as the corresponding sections of the developed branches of the airway. In another study by Walters and Luke (2010), where 50% of the airway paths were truncated, static pressure values at corresponding sections of the remaining bifurcations were used as the boundary conditions at the truncated sites.…”

Method of Constructing an Asymmetric Human Bronchial Tree in Normal and Pathological Cases

“…The upper part of the bronchial tree with well-described morphometric data is reviewed in several papers [3][4][5][6][7][8][9][10][11][12][13][14][15]. An advanced review of these investigations can be found in [2].…”

Analytical Design of the Human Bronchial Tree for Healthy Patients and Patients with Obstructive Pulmonary Diseases

“…The resultant graph of the bronchial tree contains up to seven generations. Two torus configurations were used to design an individual bifurcation in [7][8][9] (Fig. 4).…”

“…V. 14. № 2. doi: 10.17537/2019.14.635of symmetric dichotomy (symmetric bronchial tree model[1]) are defined by the following formulas[9]:• input bronchus radius (in mm)…”