vitesse de chute

PHR: Vitesse de chute des gouttelettes, des gouttes de pluie, des grêlons, de la pluie.

CONT: In the atmosphere, ... objects such as raindrops, which attain terminal velocity at great heights above the surface, may be regarded as continuously adjusting their speeds to remain at all times essentially in the terminal fall condition. The terminal fall velocity of water droplets in still air can be computed from Stokes's law for drops smaller than 80 m in diameter. Above that size, empirical values must be used.
CONT: In other words, as cloud droplets fall, air resists their downward motion and the amount of this air resistance is based on the size of the drop and its rate of fall, or velocity. The speed of the falling cloud droplet increases until the air resistance equals the downward pull of gravity and then begins to fall at a constant speed, no longer accelerating downward. This constant speed that is finally reached is called the drop's terminal velocity, or fall speed.