Experimental Investigation of Turbulent Boundary Layer-Biofilm Interactions in a Turbulent Channel Facility

The influence of in-situ grown biofilm on high Re_\tau (>3,000) turbulence boundary layer remains insufficiently understood, despite its implications for surface drag and transport in marine environment. This study presents experimental results obtained using a close-loop, optically accessible channel flow facility designed to support uninterrupted biofilm growth under controlled shear conditions using either natural assemblage or pure culture. Here, natural seawater was continuously recirculated to enable spontaneous microbial attachment and growth. Time-resolved particle image velocimetry (PIV) was employed to capture the evolution of streamwise velocity fields and turbulence statistics over four weeks. Biofilm formed rapidly at the beginning of experiments, coinciding with measurable changes to Reynolds stress distribution in the near-wall region. These results demonstrate the facility’s capability to resolve spatiotemporal interactions between biofilm development and turbulence dynamics, providing a foundation for future investigations of wall-bounded flows in biofouling environments.