Numerical Investigation of the Hydrodynamic Performance of a Flexible Training-Edge Airfoil

Abstract A two-way fluid–structure interaction (FSI) simulation was conducted to investigate the effect of trailing-edge flexibility on the hydrodynamic performance of a NACA0012 symmetric airfoil. The leading 60% of the airfoil was rigid and the trailing 40% flexible, with the flexible material having a density of 5000 kg/m 3 , a Poisson’s ratio of 0.3, and Young’s moduli of 1×10 7 , 3×10 7 , and 5×10 7 Pa. The results indicate that the flexible airfoil achieves significant drag reduction and lift-to-drag enhancement at high angles of attack. For E = 1×10 7 Pa, the lift-to-drag ratio increases by 12–27%, and the maximum drag reduction reaches 25%. Flow-field analysis shows that the periodic deformation of the flexible trailing edge delays flow separation, accelerates vortex shedding, and weakens wake intensity, thereby improving overall hydrodynamic performance. The findings demonstrate that trailing-edge flexibility enables self-adaptive flow regulation through FSI, maintaining high efficiency under complex flow conditions and providing valuable insights for the design of bio-inspired propulsion systems and low-drag hydrodynamic structures.