Research on the drag reduction and vibration attenuation performances of the fish’s surface mucus film

This study is the inaugural investigation into the drag reduction and vibration attenuation performance of mucus films naturally present on fish surfaces, leveraging nanomechanical systems for a comprehensive understanding. The mucus was collected from healthy Asian carps. Four testing groups were the fish scale surfaces adsorbed musus for 1 min, 5 min, 10 min and 30 min, respectively. Bare scale was used as a control. The mechanical and lubrication properties of the mucus film were tested using a nano scratch/indentation tester. And the vibration attenuation performance of the film was examined by a self-developed vibration excitation device. Results show that the mucus film and the surface of fish scales combine through electrostatic interactions, ultimately forming a smooth inner layer. As the adsorption time progresses, additional proteins gradually accumulate, forming a thicker outer layer. Notably, the inner layer possesses a significant lubrication effect, effectively preventing friction and wear caused by underwater sand and gravel. Furthermore, the outer layer exhibits an excellent vibration attenuation effect, assisting Asian carp in overcoming the resistance caused by turbulence and enhancing swimming speed.