Simultaneous Measurement of Liquid Surface and Wave Velocities for Falling Liquid Films

Abstract

We propose a simultaneous measurement of liquid surface and wave velocities for falling liquid films on inclined wall. The liquid surface velocity was measured using a non-intrusive technique called as laser tagging method by photochromic dye. The movement of the dye trace tagged by UV laser (λ= 355nm) was recorded by a high speed video camera and analyzed together with the movement of wave passing over the dye trace. As a result, velocity difference between wave and liquid film before the wave passing over was found to increase with increasing wall inclination angle.