Hydrodynamic effects of mucus on swimming performance of an undulatory foil by using the DSD/SST method

This paper presents a DSD/SST study of the hydrodynamic effects of mucus on swimming performance of an undulatory foil in a non-Newtonian uniform flow. As the non-Newtonian effects are dominant in the boundary layer, this model can be taken as a simple strategy to study the hydrodynamic effects of fish mucus. Based on the simulations by varying the power-law fluid behavior index, some propulsive properties including the drag coefficients, the power coefficients, and the flow fields are analyzed in detail. It is found that in addition to other biological functions, the fish mucus serves to reduce the friction, enhance the thrust, save hydrodynamic power, reduce the force oscillations, and reduce the swimming sound. This work provides a better understanding of the fish mucus effects from the point of view of hydrodynamics.