Modeling Nonaxisymmetric Off-Design Shapes of Large Scientific Balloons

摘要

The design of a large scientific balloon is usually based on an axisymmetric model, describing its shape at float altitude. However, the shapes observed during ascent are clearly nonaxisymmetric and are characterized by a number of distinctive features, including a periodic lobe pattern surrounding the gas bubble, internally folded balloon fabric, and flat winglike structures in the lower portion of the balloon below the gas bubble. In this paper, we present a mathematical model that captures the complex geometries of these off-design shapes. Real balloons are made from long tapered sheets of polyethylene that are sealed edge to edge.