Insights into the hydrodynamics of free falling wavy films

✍ Scribed by Frederic K. Wasden; A. E. Dukler

• Publisher: American Institute of Chemical Engineers
• Year: 1989
• Tongue: English
• Weight: 871 KB
• Volume: 35
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690350203

✦ Synopsis

Three isolated waves of differing amplitude and shape were selected from experimental measurements of a falling liquid film at Re = 880 for study using an algorithm developed for solution of the Navier-Stokes equations. The method computes the velocity and pressure fields as well as the velocity of the wave. The results show that large streamwise accelerations exist along with regions of recirculating flow in a moving coordinate system. These features can explain the enhanced rates of heat and mass transfer observed in wavy film flow. Computed wave velocities and wall shear stress were in reasonably good agreement with measurements. Wave velocity is shown to be sensitive to small variations in the wave shape and explains the apparent random variation of wave velocity with amplitude that has been observed experimentally. This numerical experiment points to the shortcomings of the many methods used to model large waves on falling films that have been based on parabolic velocity profiles.