We report measurements of the residual film thickness profiles resulting from the displacement of a fluid by an immiscible fluid in a 50-cm-long and 1.1-mm i.d. capillary tube. A radioactive tracer technique is used to measure the variations of the local thickness along the tube, Spatial variations of the film thickness are observed experimentally increasing with the viscosity ratio M=mu(2)/mu(1) between the displacing and displaced fluids (10(-3)

Keywords:THIN ANNULAR FILM;PRESSURE