Abstract
The authors investigate a self-excited oscillatory phenomenon of a two-dimensional confined jet with a cylinder as a downstream target, especially for both the effects of a streamwise target size a and an aspect ratio. As a result, the authors find that the jet's dominant frequency ?D can be approximately predicted by the proposed empirical formula (Hirata et al., 2011), whenever the jet stably oscillates at various values of the non-dimensional streamwise target size a/b where b denotes the length scale of the jet's breath. The effect of a/b upon the occurrence of the stable jet's oscillation is negligible at a/b≦10. Then, the occurrence can be predicted by the proposed empirical formula (Hirata et al., 2009). On the other hand, at a/b > 10, the a/b effect is not negligible. Furthermore, the authors find that the effects of the aspect ratio h/b upon both the dominant frequency and the occurrence of the stable jet's oscillation are negligible even at such low h/b as 3.
