ScholarWorks@경상국립대학교

초록

The icing phenomenon modifies the external shape of the aircraft and negatively affects its aerodynamic performance and stability. In particular, glaze ice influences aerodynamic performance significantly due to the generation of complex flows that include separation bubbles. In this study, we predicted the unsteady aerodynamics and noise generation of an airfoil with a glaze ice shape using the Lattice-Boltzmann method (LBM). The LBM simulation of the GLC305 airfoil with a dual-horn ice shape was performed at different angles of attack, and the predictions were compared against the experimental data for validation purposes. The noise analysis was performed using the permeable Ffowcs Williams-Hawking's acoustic analogy based on the aerodynamic analysis results. The flow structures of the ice-induced separation bubble were analyzed considering instantaneous turbulent features, wherein unsteady flow phenomena, such as Kelvin-Helmholtz instability, recirculation zones, and shear-layer roll-up, were observed. Furthermore, the noise analysis results showed an increase in the noise levels at low-to-mid frequencies owing to the separation bubble and thick boundary layer generated by the ice shape, inducing maximum noise in the low-frequency range. Finally, we captured a dipole-like directivity with an increasing angle of attack; the noise propagated toward the ice shape for lower angles of attack.

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