Abstract:

The flow downstream to a contraction in a tube with bleeding flow was investigated by numerical analysis. The bleeding flow was orthogonally induced with tube axis from circumferential entrance. In the analysis, axisymmetrical and laminar flow was assumed.

The calculated results were analyzed with respect to the following three parameters.

• ratio Q_b/Q of bleeding flow rate Q_b to that of flow from contraction Q.
• relative position of reattachment point of stream from the contraction and bleeding point.
• ratio d/D of diameter of the contraction d to that of downstream tube D.

From the results, it was clarified that all these parameters had the influence on the flow downstream to the contraction and pressure loss caused by bleeding flow. The pressure loss by bleeding flow could be lowered by decreasing of Q_b/Q, setting the bleeding point far downstream to the contraction, and by increasing of d/D,
Moreover, by normalizing the dimension of settings by Reynolds number in the contraction, the similarities of flow and of pressure distribution along the tube wall were shown.

Received 6 March 2000; accepted 14 April 2000