Which three key physical properties of a spray mixture significantly affect droplet size in aerial applications?

The correct answer highlights three important physical properties—Dynamic Surface Tension, Extensional Viscosity, and Shear Viscosity—that directly influence droplet size during aerial application of spray mixtures.

Dynamic Surface Tension affects how the liquid breaks up into droplets as it exits the nozzle. A lower dynamic surface tension generally allows for finer droplets because the liquid is more easily disrupted by aerodynamic forces.

Extensional Viscosity, which measures the resistance of a fluid to flow under stretching forces, plays a crucial role in determining how the spray mixture behaves when it is atomized. Fluids with appropriate extensional viscosity can produce smaller droplets as they can stretch and break apart more effectively during the spraying process.

Shear Viscosity is relevant as it describes the fluid's resistance to shear flow. It impacts the atomization process because higher shear viscosity can lead to larger droplet sizes due to the fluid's greater resistance to flow, which affects how easily the liquid can be atomized into smaller droplets.

In summary, these properties together define the behavior of the spray mixture in an aerial application, particularly in terms of its atomization and resulting droplet size, making them crucial for effective and efficient pesticide application.