RT Journal Article ID 4295b80176ff3289 A1 Kobayashi, Kenichi A1 Morishita, Kazuyuki A1 Kato, Yuzo A1 Yoshida, Hideo A1 Echigo, Ryozo T1 MEASUREMENT OF THE EVOLVING LARGE EDDIES IN AXISYMMETRIC JETS FROM TRAVERSING CAMERA BY USING THE CROSS-CORRELATION TECHNIQUE JF Journal of Flow Visualization and Image Processing JO JFV YR 1998 FD 1998-06-01 VO 5 IS 2 SP 105 OP 113 AB To investigate the evolving process of the large structures in turbulence, an image-processing technique with a camera traversing at mean axial flow velocity was developed and applied to vortex rings and axisymmetric jets. In order to obtain the complete velocity profiles in one run, the traversing unit for a CCD camera was controlled by a personal computer to synchronize the traversing rate and the eddy motion. Video signals from the CCD camera were recorded continuously by a VCR with two binary bar codes: one to identify the video field, and the other to specify the camera position and the traversing rate. The cross-correlation technique was employed to obtain two-dimensional velocity distributions from the recorded images. From successive maps of instantaneous velocity and vorticity distributions, the motion of large eddies (vortex pairing, entrainment) that cannot be measured quantitatively by conventional techniques can be dynamically revealed using a traversing camera. PB Begell House LK https://www.dl.begellhouse.com/journals/52b74bd3689ab10b,24b5ac6c69b9fbd5,4295b80176ff3289.html