Lo-speed wind tunnel measurements and numerical simulations of unsteady surface pressures on a wing-slat configuration are presented. The unsteady pressures are incorporated into the acoustic formulation of Lighthill & Curle to calculate the level of noise radiated into the far-field. Three main noise characteristics of the slat are identified as: 1) vortex shredding from the slat's trailing edge (high-frequency tonal noise): 2) radiation): 3 low-mid frequency noise originated from the instabilities in the shear layer inside the cove region. The vortex shredding that usually occurs at low amplitudes is a noise source that contains both dipoles and quadrupoles. The unsteady fluctuations contain dipole sources of sound and the cove region noise mechanism includes mainly mechanism ( pressure fluctuations), the effect of visco-elastic coating was investigated. It was found that the level of fluctuations was damped by almost 600 Pa, corresponding to about 3dB in noise levels.
|Title of host publication||50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition,|
|Publication status||Published - 2012|
|Event||50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition - Nashville, United States|
Duration: 9 Jan 2012 → 12 Jan 2012
|Conference||50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition|
|Period||9/01/12 → 12/01/12|