A Numerical Study to Compare the Antifouling Potential of two Bio-inspired Antifouling Topographies Derived from the Pilot whale skin and the Zebra mussels
Authors: Felicia Wong Yen Myan , Thu Soe Pyae Phyo 
Published: July 2023

Abstract
Biofouling occurs naturally in aquatic environments when microorganisms attach to surfaces and form colonies. The destruction of equipment has occurred in a number of well-known economic sectors, including the power and water treatment industries. Large ships and boats face performance issues due to biofouling, such as increased fuel costs and drag. Inhibiting surfaces, toxic coatings, foul release coatings, and physical removal are just a few of the techniques that have been created and used to prevent biofouling. Some of these strategies are known to be expensive, not eco-friendly, and time-consuming. Inspired by the surface topography of zebra mussel shells and pilot whale’s skin, it stays biofoul free. This study’s objective is to assess the two bio-inspired topographies’ ability to prevent fouling. This study looks at how fouling organisms would respond to the hydrodynamic properties of the aforementioned topographies as well as whether geometric size and features have an effect on them. This study aims to clarify or advance our current understanding of biomimicry and antifouling technology because testing of biomimicry-based antifouling solutions is lacking. This research focuses on explaining the nature of microorganisms in water that settle on surfaces and how they react to disturbances caused by fluid flow. They don’t tend to build up on the surface due to the relationship between flow and the different sizes of the surface geometry. Test the hypothesis that the non-bounded high shear stress ripple features on the Zebra mussel’s shell have lower antifouling efficiency compared to the Pilot whale’s skin, which contributes to antifouling efficiency because of its high shear nanoridges, micropores, and gel-coated skin properties. Therefore, if the terrain size is smaller than the invasive organism, the effective range of antifouling is expected to be in the range of 100 µm - 300 µm. The performance of the two bio-inspired topographies was assessed using CFD ANSYS (Fluent) in an entirely numerical study. Two CAD-created representations of the bio-inspired topographies were positioned inside a fluid domain (5 mm, 5 mm, and 50 mm) under specific boundary conditions, including no slip walls assigned to the fluid domain walls, an inlet velocity of 0.05 ms-1, and the flowing fluid being water. Detailed surface meshing and mesh quality are necessary to prove a reliable solution. The velocity profile, vorticity, and wall shear stress of the surface were examined in order to determine the antifouling effectiveness. Utilizing contour and streamline plots, the flow over the topography models was examined. Based on the hypothesis, the results showed that not only does geometry affect microbial settlement but also size. Topographic patterns with larger sizes were associated with higher settlements of algae and barnacles in low velocity areas. Microbial settling may also be aided by the emergence of low shear stress and vorticity in the lower part of the topography. However, the high shear region that forms close to kink sites or sharp edges and the hydrodynamic disturbance near the surface both have an impact on reducing bacterial attachment. To add to this finding, it is still important for science to consider and conduct research on the novel strategy of using surfaces that mimic biological systems to reduce biofouling and other alternative methods to develop sustainable technology.