Experimental Investigation of Precipitation-Static Dischargers in Wind

Aircraft and other airborne vehicles naturally acquire
electrical charge during flight, due mainly to frictional
charging by precipitation particles such as ice, snow, rain, or
dust. If not properly managed using precipitation-static
dischargers, or p-static wicks, corona discharges can form on
the sharp edges of radio antennae, causing communication
interference that impairs flight safety. The basic operation of
these passive devices of charge control is explained by the
onset of a controlled corona discharge at the tip of the wick
whenever the aircraft acquires charge beyond the inception
threshold of the discharge. Whereas testing standards are in
place to quantify the charge dissipation rates of the wicks and
their electromagnetic noise, these typically ignore aspects
inherent to being airborne, such as sub-atmospheric pressure
conditions or wind advection. In this work, wind tunnel
experiments are conducted to characterize the behavior of
corona discharge from commercial p-static wicks, mounted in
standard testing configurations, subjected to DC voltage, and
exposed to wind. The results from this experimental campaign
reveal the effects of wind speed on the discharge properties,
including which discharge mode is being favored (e.g., glow
versus streamer corona), the streamer burst pulsation
frequency, as well as current characteristics. These
observations have implications in terms of the discharging
efficiency of p-static wicks as well as their interference
frequencies.