A coupled and multi-scale fluid-structure interaction and mass transfer model for biofilm growth simulations

The formation and development of different biofilm structures is known to be influenced by nutrients availability and flow conditions. For this reason an approach which takes in account the effect of local structure deformation and fluid flow on mass transfer is essential for the understanding of biofilm macro-scale dynamic. The objective of the present work is therefore to study the fluid-structure interaction (FSI) and the substrate transport and reaction of big growing biofilm aggregates, for which continuum models can be applied. For this purpose we propose a novel growth model for the simulation of biofilm structures development. It is based on a finite element approach, developed in our in-house research code, for the numerical simulation of a sequential one-way coupling of the FSI and the scalar transport models [1]. The biofilm growth is coupled to the other processes through a multi-scale approach and takes in account the effects of mass transfer and shear stresses. First numerical examples are run at the purpose to demonstrate the suitability of the growth model to catch the main features of growing biofilm structures. This type of approach can give an important contribution to the understanding of biofilm architectures living in a complex environment. It allows to study the development of complex and reallife biofilm structure shapes often seen in nature and industry, to understand the influence of operating conditions, and therefore can enable the control of biofilm behaviour.