Geometrical and kinematic properties of interfacial waves in stratified oil-water flow in inclined pipe

► New geometrical and kinematic data of waves in wavy-stratified liquid-liquid flow. ► Average wave shape in stratified liquid-liquid flow is for the first time obtained. ► Physical relation between wave shape and hydrodynamic stability of stratified flow. ► Data to improve models of pressure drop, holdup and flow pattern transition.