Noise Reduction Mechanism of Trailing Edge Blowing Using the Lattice-Boltzmann Method: Numerical and Experimental Analysis

Turbulent boundary layer trailing edge noise is a common problem in the wind turbine community. An active noise reduction method is the application of trailing edge blowing. A high fidelity simulation using the numerical Lattice Boltzmann method is used to identify an optimal trailing edge blowing configuration in terms of slot geometry and blowing jet velocity. The predicted aeroacoustic achievments are validated by experiments in the aeroacoustic wind tunnel (AWB) of the DLR in Braunschweig. To shed light on the underlying physical mechanisms, Lagrangian coherent structures are extracted from the numerical flow field data. They clearly show how trailing edge blowing shifts the acoustic energy from the low frequency region (turbulent boundary layer trailing edge noise) to the high frequency region (blunt trailing edge noise).