Articles techniques et présentations

We present numerical results involving microorganisms adhering to a plane surface submitted to a shear flow. The purpose is to have a better understanding of the removal mechanisms occurring during the cleaning in place of food processing equipments. The biological cell, i.e. the microorganism, is modelled as a rigid obstacle embedded in the bottom wall of the fluid domain. Shear induced stresses at the cell surface have been obtained from 3D simulations of laminar flow, using COMSOL, for several geometries, according to different microorganism shapes. First, validations were made for the case of a rigid sphere from analytical solutions of drag, lift and torque. Then, other cases such as spheroids and sticks were performed and discussed in terms of their orientation relative to main flow. These results are further used to analyse the experimental data with respect to reorientation that preceeds the detachment.