Numerical investigation of flow control using a deformable trailing edge on the S809 airfoil

Abstract

This study numerically investigated flow control on the S809 airfoil at a Reynolds number of 1 × 10⁶ via a deformable trailing edge (DTE). Two DTE configurations (straight trailing edge (STE) and wavy trailing edge (WTE)) were evaluated to assess their influence on aerodynamic performance. Oscillation parameters (frequency and amplitude) were systematically varied and compared against a baseline rigid airfoil. A hybrid two- and three-dimensional detached eddy simulations (2D/3D DES) were employed, with 3D DES simulated more realistic flow structures and showed good agreement with experimental results at large angles of attack. Results showed that both DTE designs effectively suppressed periodic vortex shedding in the spanwise and chordwise directions, enabling flow control and improving aerodynamic force coefficients. The WTE configuration exhibited a synergistic interaction between its wavy geometry and oscillatory motion, which attenuated flow separation and reduced trailing edge vortex accumulation. This led to a remarkable 54% increase in lift coefficient with a 32% drag coefficient reduction. The findings emphasized the potential of combining trailing edge motion with wavy geometry for enhancing airfoil aerodynamic performance.