Mitigate marine macrofoul growth on underwater surface using the generated wall shear stress from confined radial outflow*

Ocean vessels experience heavy biofouling pressure when stationary for extended periods of time. Deploying a vessel without cleaning the hull results in a significant reduction in operational efficiency. A neutrally buoyant and contactless grooming device utilizes confined radial outflow at a constant flow rate to detach organisms using peak wall shear in addition to securely levitating parallel to the hull at some equilibrium gap height, where the overall force generated by the fluid field is zero. Changing the buoyancy to either increase the gap height will cause a suction force to pull the pad towards the surface or decrease the gap height to push the pad away from the surface in the attempt to maintain equilibrium. Experimental fluid flow visualization using 3D Particle Tracking Velocimetry (PTV) captured the complex fluid flow in the gap. Using the same device geometry and size, a field test study was conducted with image analysis to determine the effectiveness of various grooming frequencies on biofouling growth cultivated in a temperate coastal environment.