The authors investigate a self-excited oscillatory phenomenon of a two-dimensional confined jet with a cylinder as a downstream target. As a result, the authors find that the effect of D/b can be negligible when D is more than D/b = 47. Furthermore, the author conducts two-dimensional numerical analyses based on vorticity ζ and stream function ψ. The authors reveal a good agreement between experiments and computations, which suggest that the concerning phenomenon is intrinsically two-dimensional. Finally, the author conducts proper orthogonal decomposition (POD). As a result, the first and second POD modes accurately resemble the internal jet oscillation.
