Wind tunnel flux comparisons using a phase Doppler interferometer

• Main Authors: Roten Roy L., Post Scott L., Werner Armin, Safa Majeed, Hewitt Andrew J.
• Format: Article
• Language: English
• Published: Polish Academy of Sciences 2017-09-01
• Series: Journal of Plant Protection Research
• Subjects: flux monofilament system; phase Doppler system; wind tunnel
• Online Access: http://www.degruyter.com/view/j/jppr.2017.57.issue-3/jppr-2017-0040/jppr-2017-0040.xml?format=INT

It is essential to know the movement of droplets in time and space (i.e. flux) when measuring and/or predicting spray drift in agricultural application. A study was performed to assess the flux measurements of a phase Doppler system against a standard monofilament system in a wind tunnel. The primary objectives of the study were to compare flux from a new phase Doppler system against 1.7 mm cotton and 2.0 mm nylon strings at varying wind speeds (1.4, 4.2, 8.3, 12.5, and 16.7 m · s−1) and spray exposures times (5, 10, 15, 30, and 60 s) with an overarching hypothesis that the active, phase Doppler is able to accurately measure the flux regardless of exposure and spray mass whereas the static string samplers are limited to a maximum retention. The phase Doppler did measure linearly as expected, however strings did not reach a point in which they loss mass; conversely, they appeared to overload with saturation. These findings are believed to be among many variables which influence the variability of previous mass balance studies.