aircraft
Well-Known Member
This topic may not fit here, but experience told me there were all kinds of experts in this forum!
During pesticide spraying a drop will atomize further if it has a relative speed to the air around it. The high air speed causes high air shear that will "tear" a drop apart. This kind of atomization usually is not desired because fine drops take a longer time to settle and are prone to drift and evaporation.
I guess for this reason the spraying direction is rearward in ag airplanes. If the airspeed of the airplane is V0, and the nozzle exit speed of a drop is V1, then the relative speed of the drop to air will be V0-V1, the difference between these two speeds. Is this the reason the spraying direction is reaward? Is it usually the case to match V0 to V1 so the difference V0-V1 will be small? Is there a limit how big this difference can be?
During pesticide spraying a drop will atomize further if it has a relative speed to the air around it. The high air speed causes high air shear that will "tear" a drop apart. This kind of atomization usually is not desired because fine drops take a longer time to settle and are prone to drift and evaporation.
I guess for this reason the spraying direction is rearward in ag airplanes. If the airspeed of the airplane is V0, and the nozzle exit speed of a drop is V1, then the relative speed of the drop to air will be V0-V1, the difference between these two speeds. Is this the reason the spraying direction is reaward? Is it usually the case to match V0 to V1 so the difference V0-V1 will be small? Is there a limit how big this difference can be?
