Flow characteristics in a counter-flow type T-junction

Flow characteristics for turbulent flow in a counter-type T-junction channel have been examined experimentally. The T-junction was modeled by a mixing tee with square cross sections, in which the mixing channel was connected with the main and counter channels at right angles. Detail distributions of velocity after the mixing have been measured using PIV with high spatial/time resolutions. We investigated the influence of the velocity ratio ranging 1∼5 on the flow characteristics. In addition, POD analysis, two-point correlations, and autocorrelations of velocity fluctuation were applied to investigate the unsteady behavior of the mixing layer. These results show that the spatial pattern of velocity fluctuation, which has a weak periodicity with a relatively long time scale, was conveyed downstream with stretching. (author)