Design and investigation of the hydraulic performance of bionic hydrofoil based on the geometric features of sturgeons

Abstract

The airfoils designed by the National Advisory Committee for 
Aeronautics (NACA) are currently adopted in the blades of hydraulic machinery (pump, water turbine). However, the NACA series 
are designed on the basis of the aerodynamics theory, so their 
performance are inevitably affected when they are applied directly 
to hydraulic machinery. Thus, the mechanism affecting the hydrodynamic characteristics of a hydrofoil based on aquatic organisms 
must be further investigated. In this study, a sturgeon hydrofoil 
based on the water environment was designed by using a 3D laser 
scanner, and the hydrodynamic performance of the hydrofoil was 
integrated by numerical simulation. A k–ω SST model was adopted at Reynolds numbers 1E6, 3E6, and 5E6 under 0°–27° angle of 
attack for the analysis of the lift and drag coefficients, tip vortices, 
and pressure distribution on the upper surface of the sturgeon hydrofoil as compared with those of the NACA0012 and NACA0015 
hydrofoils. Results show that the lift coefficients of the sturgeon 
hydrofoil are greater than those of the NACA0012 and NACA0015 
hydrofoils at different Reynolds numbers. The NACA0012 and 
NACA0015 hydrofoils generate and spread tip vortices easier than 
the sturgeon hydrofoil, but the sturgeon hydrofoil generates a larger lift force before reaching the stall angle of attack, especially in 
the maximum-thickness region on the upper surface. Conclusions 
obtained in the study have important implications for designing a 
bionic airfoil suitable for hydraulic machinery