实验研究钝后缘(blunt trailing edge)流场在声音产生中的应用
The unsteady lift generated by the flow of turbulence over the trailing edge of an airfoil can be aneffective source of dipole sound. The objective of the present research was to experimentally measurethe velocity field behind an asymmetric 45 degree beveled trailing edge in order to develop an understandingof the flow mechanisms responsible for the generation of trailing edge noise. Particle ImageVelocimetry (PIV) data were acquired in the near wake region of the trailing edge at a chord Reynoldsnumber of 1.9x106. The time averaged velocity statistics are indicative of a wake flow containingsemi-periodic vortex shedding. These large scale shedding motions are commonly responsible for thetonal noise produced by the trailing edge. A phase average decomposition of the velocity field withrespect to this shedding process was utilized to separate the small scale turbulent motions responsiblefor broadband sound production. This analysis has shown that the characteristics of the small scaleturbulence are dependent on the phase of the vortex shedding process.