An experiment was conducted to investigate the surface stripping and breakup lengths of a round water jet.The process of the main and the satellite droplets in Rayleigh model was further studied under low jet velocity.With the increase of jet velocity

small droplets were stripped off from the jet surface.The surface striping did not appear on the jet surface until the Reynolds number exceeded a critical value.Two jet breakup lengths(the stripping length and the pinch length) were defined and the variations of the two breakup lengths with the jet Reynolds number were plotted

and the correlations fitted for the two breakup lengths were obtained.