Phase Doppler Flux Comparisons
ASABE conference 2016, Orlando, USA
Roten, R., Post, S., and Hewitt, A.
The movement of droplets in time and space (i.e. flux) is essential to know when measuring and/or predicted spray drift via agricultural application. A study was performed to assess the flux measurements of a phase Doppler system against the standard string derived flux in a wind tunnel. The primary objective of the study was to compare flux from a new phase Doppler system against 1.7 mm cotton and 2.0 mm nylon strings at varying wind speeds (5, 15, 30, 45, and 60 km/h) and spray exposures times (5, 10, 15, 30, and 60 s) with an overarching hypothesis that the active, phase Doppler would be able to accurately measure the flux regardless of exposure and spray mass whereas the static string samplers will be limited to an undefined maximum retention. The phase Doppler did measure as linearly as expected, however strings did not reach a point in which they loss mass; conversely, they appear to be overloading. These findings are believed to be among many variables which influence the high variance of past mass balance works reported in the literature.