An experimental study of wave inception on falling liquid films

✍ Scribed by S. Portalski; A.J. Clegg

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 651 KB
• Volume: 27
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(72)80102-7

✦ Synopsis

study of the inception and growth of waves on falling liquid films is reported. Two new experimental techniques were used:

I. The instantaneous sampling of the varying film thickness at fixed points at the wetted wall using a light absorption method. The information from the digitised sampling unit was automatically recorded on punched computer tape and subsequently processed in a computer.

2. 'Freezing' of the incipient wave motion on dyed liquid films by photographic means, and using microdensitometry to produce profiles of the developing waves.

The results obtained include measurements of the wave growth rates and the variations of the maximum wave height, mean film thickness and residual film thickness in the area of wave inception. Also the sequence of growing wave profiles in the critical area of regular wave amplification and subsequent breaking up of the orderly wave flow was recorded.

Three liquids were investigated, water and two glycerine solutions. It was shown that the mean film thickness increases slightly after the inception of waves, and a study of the ratio of the rate of rise of waves to the rate of fall of the waves has led to an explanation of the development and growth of the wave motion.