The unsteady lift generated by the flow of turbulence over the trai領(lǐng) edge of an airfoil can be an effective source of dipole sound. The objective of the present research was to experimentally measure the velocity field behind an asymmetric 45 degree beveled trai領(lǐng) edge in order to develop an understanding of the flow mechanisms responsible for the generation of trai領(lǐng) edge noise. Particle Image Velocimetry (PIV) data were acquired in the near wake region of the trai領(lǐng) edge at a chord Reynolds number of 1.9x106. The time averaged velocity statistics are indicative of a wake flow containing semi-periodic vortex shedding. These large scale shedding motions are commonly responsible for the tonal noise produced by the trai領(lǐng) edge. A phase average decomposition of the velocity field with respect to this shedding process was utilized to separate the small scale turbulent motions responsible for broadband sound production. This analysis has shown that the characteristics of the small scale turbulence are dependent on the phase of the vortex shedding process. 德國LaVision PIV/PLIF粒子成像測速場儀 Imager SX PIV相機 用于粒子成像測速(PIV)的熒光示蹤粒子