PIV Experiments to Measure the Velocity Field Just Downstream of an Oscillating Collapsible Tube

Almost all vascular conduits in the human body, being flexible, collapse elastically to a non-circular cross-section when the external pressure sufficiently exceeds the internal. Examples include the brachial artery (sphygmomanometry), veins (everyday manoeuvres), pulmonary airways (forced expiration), pulmonary capillaries (zones 1 and 2), and the urethra (micturition). Venous collapse is involved in regulation of venous return, which in turn regulates cardiac output.