CFD ANALYSIS OF VORTEX SHEDDING AND FREQUENCY CHARACTERISTICS OF A NACA 63-415 AIRFOIL AT HIGH REYNOLDS NUMBERS

In order to preclude vibration and resonance, the vortex shedding characteristics have been numerically simulated at Re = 1.042 × 106 using computational fluid dynamics (CFD), focus-ing on flow separation from the NACA 63-415 airfoil. In addition, the variation of vortex shedding forms and the corresponding frequency characteristics at various angles of attack are studied. The 2-D simulation consists of two stages: steady analysis and transient analysis, with ANSYS fluent utilized for this research. The purpose of steady-state approach is to comprehensively validate the model's results by comparing them with available experimental data, as well as to study grid independence. The Spalarat-Allmaras model is used for simulat-ing the airfoil in the steady-state, while the k-ω SST model is used for the unsteady part. The frequency spectrum corresponding to the lift coefficient is used to analyze the of vortex shedding characteristics from a frequency domain perspective. In other words, Power spectral densities of the unsteady lift and drag coefficients are used to determine flow characteristics. By increasing the angle of attack, the Strouhal number of vortex shedding frequency increas-es, and the stability of the flow field decreases. Large and damaging vibrations can occur if the vortex shedding frequency becomes close to the natural frequency of the structure.

CFD ANALYSIS OF VORTEX SHEDDING AND FREQUENCY CHARACTERISTICS OF A NACA 63-415 AIRFOIL AT HIGH REYNOLDS NUMBERS Keywords:

Vortex shedding , Lift and drag coefficients , Flow separation , Strouhal number