Trailing-edge airframe noise source studies on aircraft wings

Interaction between unsteady surface flow and wing trailing edges is considered one of the dominant source mechanisms of airframe noise. For the prediction of trailing-edge noise radiation, detailed information on the unsteady-flow behavior close to and at the edge is essential. Therefore, surface pressure measurements were conducted near the wing/flap trailing edge of a business jet aircraft (HFB-320) and a large commercial aircraft (DC-10/30) under realistic flight conditions within a wide range of flight speeds and typical flap deflection angles. The spectral distribution of pressure intensities and coherences were determined and compared to corresponding results from model and glider measurements, respectively. On the basis of integral pressure field coherence dimensions (deduced from measured data), the applicability of the hydrodynamic trailing-edge noise model is evaluated.