Boundary-Layer Separation and Vortex generations in a Suddenly Blocked Pipe

The flow of a fluid in a pipe which is suddenly blocked exhibits a broad class of interesting fluid dynamical phenomena, including transient turbulent, unsteady boundary-layer separation and vortex generation. Away from the blockage the flow is unidirectional and governed by a simple temporal diffusion equation ([1] and [2]). The flow in this region is linearly unstable, exhibits transient disturbance growth and also transient turbulent events ([1-3]). In the vicinity of the blockage the flow is no longer unidirectional. This paper will describe the flow in this end region from the instant of blockage through to the eventual decay of the flow.Jim Denier and Nathaniel Jewel