Wall shear stress in an upward slug flow in a vertical tube

This paper deals with wall shear stress in an upward gas-liquid slug flow inside a vertical tube. Local characteristics were measured by the electrodiffusion method. The method of conditional averaging over realization ensemble was used, and this allows distinguishing large-scale structures on the background of turbulent pulsation of liquid. While averaging, each slug velocity measured by a double probe of electric conductivity was taken into account. Averaged distributions of shear stress over the wall under a gas slug were obtained for different mode parameters. The work was financially supported by the Russian Foundation for Basic Research (Grant No. 04-01-00328) and the Russian Science Support Foundation (Grant “The Best Post-Graduate of RAS-2006”).