突起物による発振噴流の制御と流れ特性

抄録

The purpose of this study is to suppress edge tone generated by jet-wedge interaction. A passive control was achieved by means of a pair of tabs attached to the center of the nozzle exit, and revealed that the edge tone is reduced by 5dB. Velocity measurement was also conducted to clarify the suppression mechanism by use of sound wave excitation. The excitation was synchronized with the self-oscillating flow for selective sampling, so that hot-wire measurement directly provide the phase averaged flow fields. It was revealed that the velocity is weakened at the position corresponding to tabs, and the spanwise uniformity of the jet is broken. In addition periodic fluctuation of vorticity is reduced by tabs. These phenomena weaken feedback loop, as a result the edge tone was suppressed.