Optimizing Water Flow With Cavitation on the NACA 0009 Hydrofoil Inspired by the Mako Shark Bumps

The numerical investigation of the water flow with partial cavitation around the NACA 0009 hydrofoil with bumps inspired by the mako shark (biomimicry) was performed. The simulation was done by ANSYS Fluent software for cavitation numbers of 1 and 1.5 at flow speeds of 5 and 10 m/s and various angles of attack from 4° to 12°. The effect of bumps and their related parameters, including number, thickness, and installation location, has been investigated in conditions without and with cavitation. The hydrofoil with the highest lift‐to‐drag ratio was selected for each angle of attack. The results show that the formation of a patterned bump inspired by the surface of the shark skin can affect the lift and drag coefficients by affecting the cavitation and separation phenomena. If these bumps are installed in the right number and place, they can reduce the drag coefficient and increase the lift coefficient. At a water flow speed of 10 m/s and a cavitation number of 1.5, the bumps had a good performance causing an increase in the lift‐to‐drag ratio from the angle of attack of 6°. However, at a flow speed of 5 m/s and a cavitation number of 1, the improvement of the lift‐to‐drag ratio starts from the angle of attack of 4°. Among the various parameters examined in this research, which were also confirmed by the Taguchi method and Minitab software, the most influential parameters are the installation location and the number of bumps. The hydrofoil with two bumps at a chord length position of 13% with a chord length thickness of 1.14 mm at a 6° angle of attack had the best performance that caused an increase in the lift‐to‐drag ratio up to 40% in a cavitation number of 1.5 and a flow speed of 10 m/s.