Mesoscale study of turbulent boundary layer over an in-situ grown soft fouling

Biofouling of ship hulls is a ubiquitous phenomenon and causes substantial maintenance costs each year. While real-world flow near a ship hull is highly turbulent, past laboratory studies focus largely on understanding of biofilm formation mechanisms and identifications of phenotypical responses by microbes to a wall under low and laminar flow shear. Recent findings on formation of biofilms in turbulent flows capable of resisting shear have reignited interests in interactions of turbulent flow and biofilm. To provide new insights on flow and soft-fouling interactions at scales relevant to real-world applications, we developed a mesoscale flow facility enabling the study of in-situ biofilm formation at high turbulent flow shear conditions. The flow facility is instrumented for simultaneous biofilm measurements and the near-film flow field via coupled particle image velocimetry (PIV) and planar laser induced fluorescence (PLIF) systems. Results on hydrodynamic interactions of turbulent boundary layer (TBL) and in-situ grown biofilms from natural seawater are presented. The temporal evolution of TBL at different growth stages is investigated.