Laminar jet flow into a dead-end tube

A model of artificial lung ventilation consists of a laminar jet issuing into a concentric dead-end tube. The jet must reverse its direction, flow opposite to the jet, and exit through the annulus between the jet tube and the dead-end tube. This flow was studied using flow visualization and Particle Image Velocimetry. The ratio of the jet tube diameter to the dead-end tube diameter was 0.10, 0.20, and 0.30. The jet Reynolds number was varied from 50 to 400. The maximum penetration depth of the jet into the dead-end tube increases with Reynolds number. For a given Reynolds number the jet penetration depth increases slightly with decreasing diameter ratio, probably as a consequence of the reduced reverse flow rate associated with the larger annular area as the diameter ratio decreases. The velocity fields measured using PIV show a long annular recirculation zone between the jet and the reverse flow.