Although substantial advances have been done in parachute technology over the past three decades, parachute design is still largely based on a combination of analysis and empirical observation. This is particularly true of work done in an attempt to analyze the time-varying behavior of a parachute during inflation or partial collapse. The lack of any suitable testing apparatus for determining the internal and external flow fields associated with filling and collapse would appear to be a major reason for the lack of comprehensive studies in this area.
Prior art parachute testing devices and systems include wind tunnel testing of parachute canopies and the use of water flow table models to simulate the flows thought to be involved. The former technique suffers a number of disadvantages including confusion of the airstream lines due to the three dimensional flow propagation of the smoke particles used in determining the flow fields, the "blanking" of internal flow by the "near side" (observer's side) of the canopy cloth, and the inability of the flow velocity and pressure sensing devices to occupy the volume of space through which the canopy must extend. In fact, water table models were used because of the many problems associated with wind tunnel testing of actual or scale model canopies. However, such models simply do not provide accurate simulation of the phenomena in question. In particular, the liquid velocities and mass relationships in such testing arrangements are so unlike those actually encountered with actual parachute canopies that new problems were created regarding relating mass, velocity, viscosity, and scale relationships to actual conditions.