FLUID-DYNAMICS IN COLLAPSIBLE TUBES - PRE SSURE DISTRIBUTION AND RESISTANCE CHARACTERISTICS

Regarding a collapsible tube with low downstream resistance, the press ure distributions were measured with Pitot tubes, which were inserted from the downstream bifurcation part. Examining the result of total pr essure distributions, it was found that there are a high speed jet at the throat and a ceased water region just after the throat. It was als o indicated from the static pressure distributions that the effective flow section area might be far smaller than the geometric section area of the tube. Concerning this, the flow visualization disclosed asymme tric flow separation. On the other hand, the measurement of throat pre ssure vs. flow rate clarified that the resistance between the throat a nd the downstream outlet does not necessarily cause self-excited oscil lations.