S054104 密度差を伴う旋回噴流の渦崩壊現象([S05410]噴流,後流,およびはく離流れの基礎と応用:最前線(10))

概要

論文の詳細を見る
We experimentally studied the change in vortical structure of a variable property jet with swirling flow, focusing on the behavior of a stable vortex breakdown phenomenon. Air, CO_2 or He is issued from the inner jet while the outer jet issues air to vary the property of the jet. Both the inner and outer jets are rotated in the same direction; counter-clockwise. The flow field was visualized using the laser tomographic method, and its velocity fields was obtained from particle image velocimetry (PIV). Vortex breakdown not only forms easier in a high-density, low-viscosity jet, i.e. the CO_2 jet, or under a swirling outer jet condition, the height of the stagnation point also decreases. The vortex breakdown does not occur in the He jet even at high swirl numbers. Furthermore, its overall behavior remains nearly unchanged throughout the entire range of inner jet swirl. We propose a theoretical equation from which the change in stagnation point location can be physically explained. This equation succesfully explains the trend of change in the stagnation point location.
一般社団法人日本機械学会の論文
2011-09-11