A low-cost CAA (Computational Aeroacoustics) method has been applied to make slat noise predictions with an computational effort in the range acceptable for a design tool. The turbulence related slat-noise sources are modeled with a random particle mesh (RPM) method, which matches the statistical features of a steady RANS (Reynolds Averaged Navier-Stokes equation) target solution quite closely. A modified two-element airfoil, consisting of a slat and a main element, is used for the slat noise predictions. The slat noise directivity found from the computations roughly corresponds to that of a dipole located at the slat trailing edge with its axis normal to the slat chord. The characteristics of narrow as well as 1/3-octave spectra agree with those found from measurements. The slat noise is found to scale with the 4.3 power of the Mach number. The effect of a slat cove cover was furthermore investigated. Reductions around 5dB in a range up to 8kHz (based on 0.4m clean chord length) are found in the narrow band spectra, clearly indicating a potential of slat cove fillers to reduce sound levels.
Slat noise predictions based on APE and stochastic sound sources from RANS
Vorhersage des Vorflügelgeräusches auf der Grundlage der akustischen Störungsgleichungen und stochastischer Schallquellen aus den Reynolds-gemittelten Navier-Stokes-Gleichungen
2006
10 Seiten, 12 Bilder, 18 Quellen
Aufsatz (Konferenz)
Englisch
SLAT NOISE PREDICTIONS BASED ON APE AND STOCHASTIC SOUND SOURCES FROM RANS
British Library Conference Proceedings | 2006
|Prediction of Slat Broadband Noise with RANS Results
AIAA | 2015
|