LAUSR

Abstract We consider a vertical cantilevered pipe conveying fluid, located in a container filled with the same fluid; the upper portion of the pipe is surrounded by a rigid cylindrical tube of larger diameter, thus forming an annular fluid-filled region around the pipe. Two flow configurations are investigated: (a) the fluid enters the pipe at its clamped upper end and flows downwards, discharging at its free lower end into the container; the fluid exits the container by flowing upwards in the annulus and out; (b) the reverse flow arrangement, in which the fluid enters the system at the upper end of the annulus and exits by flowing upwards in the pipe. The dynamics of the system is studied theoretically for both configurations (a) and (b) and experimentally in an in-house bench-top apparatus. The analytical models utilized, with some CFD input, are outlined, and the bench-top experiments are described. For given parameters, both theory and experiment find that the system loses stability at sufficiently high flow velocity by flutter or static divergence. Finally, theory and experiment are compared, showing reasonable to good agreement for flow configuration (a), but less than satisfactory agreement for configuration (b).