Abstract
A two-dimensional incompressible turbulent jet issuing nearly parallel to a side-wall of finite length develops the pattern of either a reattaching flow or a separated flow. When the side-wall is long enough, the jet reattaches naturally to the wall. The jet is thought to be unstable and separate, if the wall is considerably short. In the present paper, an analytical model is discussed. The calculated results for steady phenomena of a wall-reattaching jet show good agreement with experiments. Experimental observations showed even if the wall length is shorter than the offset distance, the separated jet can be forced to reattach to the side-wall by an instantaneous control flow and be kept stable. Therefore, from the viewpoint of controlling flow direction or flow state, three regions along the wall, length are defined as follows: (I) Natural reattaching region-when the side-wall is long enough, the jet reattaches naturally to the wall. (II) Bistable region-in a certain section of the wall length, both the separated flow and the forced reattaching flow are possible, either of which is selectively chosen by a control flow and kept stable. (III) Separated region-the jet never reattaches, if the wall is very short. These three regions are distinctively divided by two lines; a natural reattachment limit line and a forced reattachment limit one. It was confirmed that Reynolds number has no influence either on the overall flow pattern, or on the detailed construction of the flow.
