Broadband Trailing-Edge Noise Predictions using Incompressible Large Eddy Simulations

Incompressible large eddy simulations of the flow over an airfoil at high Reynolds number and low Mach number have been performed, including simulation of bypass transition to turbulence, and trailing-edge noise predictions. Extensive data comparison and validation has been carried out, using benchmark data and additional results from literature. Three semi-analytical noise models - Curle’s acoustic analogy, the Ffowcs Williams-Hall (FW-Hall) model, and Amiet’s model - were applied, with the sensitivity of the results to the hydrodynamic input data investigated. Overall, a good agreement was found between experimental and numerical results in terms of hydrodynamics. The main discrepancies were an overprediction of the Reynolds stresses close to the wall, and the high-frequency part of the turbulent wall pressure spectrum, both at the trailing edge. It is hypothesised that this is caused by the underresolved transition of the boundary layer. In terms of the acoustic predictions, the FW-Hall and Amiet models perform better than Curle’s analogy, with Amiet giving the best agreement with measurements below 2 kHz, and FW-Hall being superior above this frequency, with the latter model identified as being less sensitive to the aforementioned errors in the hydrodynamic results.