On biomimetic surface texturing and its impact on turbulent flow and hydrodynamic forces acting on an early-stage bio-fouling organism

Recent marine anti-fouling research efforts have sought inspiration from bio-mimetic strategies to develop nontoxic solutions. Surface modifications have shown promising results in their ability to disrupt attachment and growth of early-stage organisms under static immersion conditions but very limited research has attempted to explore the interaction between surface textures and flow under turbulent conditions. The study presented in this article focuses on a simple texture, inspired by the growth rings of the Brill fish Scophthalmus rhombus and developed for applications on the blades of tidal stream turbine. A series of Large Eddy Simulations of fully developed turbulent channel flow were performed to assess the influence of the spacing between the texture elements on turbulent stresses. The aim is to characterize the impact of the texture on turbulent stresses by comparison to a smooth surface and identify whether shelters may form within the gaps between textures. The study clarifies the role of dispersive and Reynolds stresses in terms of their impact on hydrodynamic forces acting on a simplified model of a marine diatom. Reynolds shear stresses predominantly govern the intensity of forces, while dispersive shear stress affects the mean hydrodynamic forces acting on the organism at the early stage of settlement.