2) Circular motion around a droplet. The fleeing probability of a particle inside the system is extremely low by avoiding collisions when moving along the radii directions. Particles must be confined by a droplet acting as partners in the evaporation-condensation process. Some particles circularly move around a droplet to form the boundary layer among them. It does not directly work towards the droplet and the outer surroundings. However, it triggers the periodic fluctuation of VG along the orbital, producing a ball-type VG wave spreading to the whole gas phase of a droplet. Indeed, the particle itself will be impacted to produce the orbital wave. These waves do not release the energy at the equilibrium but cause the harmonic vibration of evaporation-condensation equilibrium. It may be the so-called tidal force. Therefore, changing the waves means damaging the equilibrium.