EXPERIMENTS ON STEADY AND OSCILLATORY FLOWS AT MODERATE REYNOLDS-NUMBERS IN A QUASI-2-DIMENSIONAL CHANNEL WITH A THROAT

The study of steady and unsteady oscillatory static fluid pressures ac ting on the internal wall of a collapsible tube is essential for inves tigation of the complicated behavior observed when a Polo is conveyed inside a tube. To examine the validity of two one-dimensional nonstead y theoretical flow models, this paper presents basic experimental obse rvations of flow separation and reattachment and measured data on the static pressure distributions of the Polo in a quasi-two-dimensional c hannel with a throat, together with information on the corresponding s hape of the wall deflection and motion. For combinations of moderate R eynolds numbers and angles of the divergent segment of the channel, a smooth flow is separated from the wall downstream of the minimum cross section and reattached to the wall farther downstream. The measured d ata are compared with numerical results calculated by the two flow mod els.