柔性喷嘴的喷射流场结构相互作用效应研究

Pulsed jets have found a wide variety of applications in the area of flow control during the recent years. The goal of the current study is to identify the flow field and mixing characteristics associated with an incompressible circular jet through a flexible nozzle. The flow was self-excited over a range of conditions and produced a pulsatile flow. The frequency of excitation was found to be between 150-175Hz. Phase-locked and time averaged 2D Particle image Velocimetry (PIV) was used to study the dynamic characteristics of the flow. The flow field shows that two different modes could be excited depending on nozzle characteristic. The flapping mode was associated with alternate shedding of vortices. This introduces strong steering of the jet to one side or the other. Turbulence, Jet spread and entrainment characteristics were far more superior to the non-flapping or a pulsed jet. The second mode which was a non-flapping mode is associated with the formation of a counter rotating vortex pair. The turbulence associated with both these modes was convected along with the vortical structure in the flow. The jet vortices formed by the self-excited flow were not just convected by the flow, but these determined the flow field and mixing characteristics of the jet. 德国LaVision PIV/PLIF粒子成像测速场仪 基于片状激光照明成像的先进喷雾测量系统 Artium PDI-FP 双量程可机载飞行探头