Particle Image Velocimetry Measurements of the Flow over Barnacles in a Turbulent Boundary Layer

Abstract

Barnacles are suspension-feeding crustaceans found in saline waters. Past research has focused on the hydrodynamics of larvae settlement and recruitment. These fouling organisms can grow on the hull of marine ships, thus having a significant impact on their performance. The presence of barnacles dramatically increases the frictional drag and consequently has drastic negative economic implications. High-resolution Particle-Image Velocimetry is used to measure the flow over barnacles immersed into a turbulent boundary layer. Two configurations were investigated - i) single-barnacle configuration and ii) a regular, staggered array of barnacles. Mean flow quantities between these two configurations are strikingly similar when visualizing the flow around an individual element. Quadrant analysis revealed important structural behavior, especially when only considering the strongest Reynolds shear stress events. These events are likely linked to contribute to both larval settlement and waste removal.