Stability analysis for noise-source modeling of a part-span flap

The relevant and important flow features of the local mean flowfield in the vicinity of a flap side edge are extracted from an extensive computational and experimental database. Based on the local how features, possible mecha nisms for how-induced noise sources that are responsible for sound generati on at flap side edges are conjectured. Relatively simple how models for the dominant mise sources are proposed and developed. The models are based on the most amplified instability modes of the local shear how, Stability anal ysis of the modeled flowfield provides an estimate of the frequencies assoc iated with the local flow unsteadiness. Computed frequencies show the prope r trend and are in good agreement with NASA Langley Research Center's acous tic microphone array and unsteady surface-pressure measurements.