抄録
The simulaneous measurement of the velocities at two points with X-type hot wire probes has been performed in three different downstream regions of a plane jet (i.e., the potential core region, the interaction region and the self-preserving region). Mainly by the combined analysis of KL expansion and Fourier transform, the structure development of the plane jet is investigated from a viewpoint of both space and frequency. From the downstream variation of the eigenfunctions, it is found that in the early stage of the interaction region the profiles of the 1st u- and v-POD mode in the low frequency range become self-similar, but in high frequency range these continue to change until the self-preserving region. The characteristics of coherent structure can be extracted efficiently by the spatial correlation profiles reconstructed from the 1st POD mode.
