No abstract

No abstract

Airway mucus is difficult to clear and to improve lung function clearance of mucus is necessary. The deep coughing, chest physiotherapy, high frequency chest wall oscillation etc. are some of the best methods to clear excessive mucus from lung airways. In this article we analysed the behavior of fluid flow between parallel walls , where both walls are porous and the flow is induced by the oscillation of these walls and pressure gradient; which is applicable for clearance of mucus from lung airways. Generalized couette flow is applicable to model the oscillation of parallel walls, however the laminar flow of viscous fluid is taken under consideration. The generalized Navier-Stokes equations are applied to make various hypotheses and finite difference scheme is used to solve the problem numerically. Effect of wall oscillation, wall porosity, pressure due to porous media on mucus clearance and particle aspect ratio on the deposition of nonspherical nanoparticles are analysed graphycally after simulating the problem on MATLAB R2013a by user defind code. Simulation show an excellent agreement of unsteady flow of viscous fluid at large values of time and significant correlation between pressure gradient and porosity of walls, frequency of wall oscillation and their imapct on mucus clearance are obtained. In addion it is observed that fluid and particle velocity are increased with the enhancement of media porosity, breathing frequency and aspect ratio. The aim of this paper is to study the influence of wall movement, wall porosity, pressure on wall, wall oscillating frequency on the clearance of mucus from lung airways.

In this study, we aimed to find the effect of periodic permeability on the flow dynamics of an incompressible, Newtonian, viscous and pulsatile flow of air flowing through airway generations 5-10. To solve this problem, we used a generalized Navier Stokes equation by including the Darcy law of a porous media with periodic permeability for the flow of air and Newton equation of motion for the flow of nanoparticles. The finite difference explicit numerical scheme has been carried out to solve the governing nonlinear equations and then computational work is done on MATLAB R2016 by user defined code. After performing numerical computation we found by varying mean permeability of porous media velocity of air and particle increased gradually with axial and radial distance respectively.

Smoking and pollution are highly hazardous to human health. Most of the environmental particles are very small in size i.e. micro or nanoparticles. When these particles are inhaled, they enter from the nose and flow with the air stream into various portions of the lungs. The alveolar region, a porous media due to number of alveoli, serves as an internal biofilter medium to filter deposited particles. To analyze the behavior of this biofilter medium, we considered the periodic permeability of lungs (due to periodic breathing) together with the viscoelasticity of the lung tissues. The flow of viscous air through the porous media is modeled by using one dimensional momentum equation with Darcy's law and the velocity of particles by second law of Newton. To model the viscoelasticity, we used Kelvin-Voigt model. The finite difference method is used to solve the governing equations and MATLAB is used to solve the computational problem. The effects of various parameters, such as the Darcy number, porosity, and the breathing frequency are analyzed for flow of air, particle and viscoelasticity of lung graphically. Results show that by increasing the breathing frequency, decreasing the porosity, and decreasing the Darcy number, the viscoelastic stress increases.