Review and Assessment of USAF and U.S. Army (HISS) Artificial Icing Cloud Studies

摘要

Artificial clouds were generated by an airplane or a helicopter spraying water through a bank of nozzles towed directly behind the aircraft. A trailing test aircraft was flown into the spray cloud; icing was induced on various surfaces of the test aircraft by exposing selected surfaces. In the flight tests conducted in the late 1970's, it was found that the droplets from the artificial cloud were too large, and the clouds were too small in size. In order to reduce the droplet size extensive work was performed in the N.A.S.A Lewis icing wind tunnel to select a more appropriate nozzle to achieve smaller droplet sizes, and to evaluate the effects of nozzle orientation and various flow parameters on the nature of artificially generated clouds. A design clinic team of graduate students has undertaken a study of the USAF inflight and wind tunnel test programs. The purpose of this study was to review the accumulated data and the experimental methods involved. An attempt was made to evaluate the quality, validity, and the direction of the work performed thus far, and to suggest ways to improve the experimental procedure and possibly present fresh ways to view the problem.