Airflow Effects on Riming Measurements by a Wing Tip-Mounted Ice Detector on the MC130E Research Airplane

摘要

Sampling efficiencies for water drops in the diameter range 10 to 7000 microns are calculated theoretically at four proposed mounting sites for an icing indicator instrument on the wing tip of the AFGL MC130E airplane. Significant flux distortion of droplets in the diameter range 10 to 100 microns is indicated at all four sites. Sensitivity to angle-of-attack of the airplane also is found, and a nose-up angle-of-attack of at least 4 deg. is recommended. Additional separation of the sensor probe from the wing tip surface of as little as one-half inch is indicated to substantially ameliorate the sampling problems. To obtain the sampling efficiencies, trajectories were calculated with use of a three-dimensional flow code that ignores effects of lift vorticity. Exploratory calculations with a similar code that includes lift indicate that the results obtained with the non-lifting flow are optimistic.