Fluid-structure interaction modeling of lactating breast: Newtonian vs. non-Newtonian milk

• Published in: Journal of biomechanics Vol. 124; p. 110500
• Main Authors: Azarnoosh, Jamasp, Hassanipour, Fatemeh
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 19.07.2021; Elsevier Limited
• Subjects: Breast feeding; Breast milk; Breastfeeding & lactation; Compression; Computational fluid dynamics; Flow velocity; Fluid-structure interaction; Geometry; Human milk; Interaction models; Mathematical models; Milk; Non-Newtonian fluid; Non-Newtonian fluids; Rheological properties; Rheology; Shear stress; Shear thinning (liquids); Simulation; Suckling behavior; Unsteady flow; Veins & arteries; Velocity; Viscosity; Yield stress; Human milk; Computational fluid dynamics; Fluid-structure interaction; Non-Newtonian fluid
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/j.jbiomech.2021.110500

Breastfeeding is a highly dynamic and complex mechanism. The suckling process by the infant involves compression and intra-oral vacuum pressure, leading to milk expression from breast. The accumulated milk from the nipple varies depending on the milk properties and transient flow rate during the suckling cycle. Rheological studies on raw human milk indicate that milk has a non-Newtonian shear-thinning flow behavior. This study aims to investigate the effect of non-Newtonian milk on flow behavior through the breast ductal system using fluid–structure interaction (FSI) simulation. The results of the non-Newtonian effects on flow velocity and the volumetric flow rate of expressed milk are presented. The results show that non-Newtonian Carreau model is promising for the simulation of human milk flow through the breast ductal systems. Also, the results show that the non-Newtonian effects on the milk flow behavior appear for 30–35% of the suckling cycle. Therefore, the Newtonian model is acceptable for the purpose of numerical simulation.