Experimental Study of Reattachment of Two-dimensional Jet

Abstract

When a fluid is ejected through a nozzle into a duct filled with the same fluid, the flow direction of the jet is deflected towards the side wall by the recirculating eddy generated near the nozzle. This phenomenon is called the Coanda effect.
To find a method for preventing the Coanda effect, we observed the flow pattern of the jet and also measured the position of reattachment, velocity distribution, and pressure distribution on the side wall of the duct when an air stream was supplied from the side wall or from an offset wall parallel to the axis of the jet.
It was found that the position of reattachment was displaced downwards as the amount of surrounding flow increased and that the recirculation eddy and the deflected flow could be successfully prevented when a surrounding flow rate was supplied equal to the flow rate entrained by the jet.