The flow behind a backward facing step interacted by the wake generated by the wire located at various heights at plane of the step face was studied experimentally.
The main objective was to investigate the variation of reattachment length with wire location.
The experiment was conducted in the sudden expansion duct of 5 cm width and 3 cm height, with step height of 1.5 cm which gives the aspect ratio of 3.33. Detailed survey of the flow field was carried out by the hot wire anemometer and the single component laser doppler velocimeter.
When the wire was located near the step, the reattachment length was longer than that of the nominal case (i.e. the case without wire). As the wire moves upward, the reattachment length gets shorter upto approximately 5 step height, which is about half of step height shorter than the nominal value and then gradually gets longer toward the nominal value.
The flow field corresponding to the wire height of 0.34 step height from the step edge, which yields the shortest reattachment length, is seen to be highly three dimensional compared with the nominal case.
