A Buoyancy-Propelled-Test-Body Laboratory Facility

The physical form of a buoyancy-propelled-test-body facility and some preliminary test results are described. The facility is a 26-meter-high, 1.067-meter-diameter standpipe which can be filled with water or other liquid. An axisymmetric body rises by buoyancy and is guided up the center on a taut restraining cable. Sensors for measurement of velocity and displacement are incorporated into the guide cable. The standpipe is also equipped to provide pull-down and release of the test body, initial acceleration, and stopping. The confined space of a standpipe within the laboratory permits controlled use of drag reducing polymer in the test liquid and nucleus removal to reduce cavitation. The minimal quantity of fluid in motion resulting from this configuration and consequent low level of background noise allow surface pressure fluctuations and radiated noise to be measured. Preliminary measurements of surface pressure fluctuations are reported. The potential of this apparatus for future use is outlined.