Flow and acoustic characteristics of isotropic turbulence interacting with a symmetric airfoil

The present study performs numerical simulations of grid-generated isotropic turbulence impinging on a symmetric airfoil at different angles of attack by utilizing the lattice Boltzmann solver PowerFLOW. The grid was chosen to match that from the experiment to provide evidence that by placing a physical grid upstream of the airfoil, the present numerical approach can reproduce the turbulence impingement process observed from the experiment and thus accurately capture the turbulence-interaction behavior and the associated noise. Both the near-field turbulence statistics and far-field noise are bench-marked against an existing experimental study. The comparison of the results shows that the turbulence intensity and integral length scales are highly consistent with the experiment. Moreover, the near-field hydrodynamics in the vicinity of the stagnation point and the unsteady wall pressure fluctuations of the airfoil also show good agreement with experimental data. The present study confirms that the grid-generated approach is suitable for the numerical investigation of turbulence interaction with airfoils and provides further insights into the deformation of turbulent structures due to the presence of an airfoil from low to moderate angles of attack. The extensive results can be potentially explored for developing noise mitigation strategies.