Turbulence Structure on the Surface of High Speed Liquid Jet

The structures on the surface of high-speed capillary liquid jet were captured with the help of high-speed camera and microscope. A power spectral density method is used to deal with the jet images. Based on captured jet image, the variation of surface structures near the exit of the nozzle is divided into three sections: laminar section, instability section and turbulence section. There is no clearly surface structures in the laminar section. The wave-like structures come out in the instability section with a sudden and are regularly increase with a small slope along the streamwise. The degree of order is rather weak in the turbulence section. The increase of the Reynolds numbers which based on the momentum thickness at the exit of the nozzle will accelerates the jet surface transition from the laminar section to turbulence section.