An experimental study on the mobility of droplets in liquid-liquid Taylor flows within circular capillaries

•An experimental study was performed to investigate droplet mobility in Taylor flows.•A novel, fully automated, experimental setup was designed for droplet measurement.•Above a certain LD/D threshold, droplet velocity becomes independent of its length.•Buoyancy forces are shown to greatly impact the mobility of short droplets.•A new correlation is presented to better estimate the velocity of elongated droplets.