The Local Motions of a Payload Supported by a Tritethered Natural Shape Balloon.

摘要

The report compares the payload motions during flights of a 793cubic meter (28,000cubic feet) natural-shape balloon on a tritethered cable array with those using an identical balloon on a single cable. Nominal altitudes were 457 m (1500ft), 610 m (2000ft),and 762 m (2500ft) above ground level at Holloman AFB and White Sands Missile Range,New Mexico. Winds ranged from 0.5 m/sec to 12 m/sec (1to 23knots). The payload location relative to the balloon was varied and the balloon was flown with different values of free lift and elevation angles. Target position,tangential speed,and acceleration were determined by using the WSMR cinetheodolite system. Telemetry included pitch and roll gyros, a flux-gate compass,accelerometers,and an anemometer. With both types of cable arrangement,one component of the motion was an oscillation similar in order of magnitude of frequency and orientation to the classic transverse oscillations of a sphere due to periodic vortex shedding in its wake. (Author)