Investigation on Critical Airflow Velocity About Departure of Droplet from Horizontal Wall

Deals with a droplet on the horizontal wall with airflow over the wall.Based on the derivation of the interfacial shape of the droplet under the critical airflow velocity,the contact angles over the contact line were obtained.Using the hysteresis tension model,a mechanical equilibrium equation describing the dynamic behavior of the droplet departure was derived.The calculation results showed that both interfacial forces and wind force increase with increasing the airflow velocity.At the low airflow velocity the interfacial forces dominate over the wind force.With increasing the airflow velocity,the wind force increases more quickly than the interfacial forces,resulting in that the critical airflow velocity is higher for the droplet with smaller diameter.Furthermore,the distance from the drop to the leading edge of the wall also affects the critical airflow velocity.As the distance increases the critical velocity increases and the more great the diameter of the droplet becomes,the more prominent L affects.