CaltechAUTHORS
  A Caltech Library Service

Fundamentals of a liquid (soap) film tunnel

Beizaie, M. and Gharib, M. (1997) Fundamentals of a liquid (soap) film tunnel. Experiments in Fluids, 23 (2). pp. 130-140. ISSN 0723-4864. https://resolver.caltech.edu/CaltechAUTHORS:20130912-093505922

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20130912-093505922

Abstract

The continuously running liquid film tunnel (LFT) is a novel device suitable for the study of two-dimensional flows. In this innovation, the films start from a reservoir, run over a horizontal or non-horizontal wire frame and get pulled/washed by a water sheet or by gravity of liquid film. How-ever, despite the simple design and widespread application of LFT, its working mechanisms are not well understood. In the present work, an experimental effort for explaining these mechanisms is reported. The results show that both film velocities and film flow rates increase with water sheet velocity up to a saturation level. This behavior is described via a force balance between the shear force produced by the water sheet and the opposing pulling force of reservoir and boundary layer frictions. The results also show that the average film thickness depends on the surfactant concentration. This is as predicted by a model based on Langmuir’s adsorption theory, in which the liquid film contains two external monolayers of surfactant and a slab of surfactant solution in between. When a film is drawn from the reservoir to the water sheet, the surfactant molecules start migrating from the former to the latter. To restore the thermodynamic equilibrium, the dragged film pulls more surfactant due to Marangoni elasticity, and thus a flow is established. The film flow soon reaches an equilibrium rate as required by the force balance mentioned above.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1007/s003480050094 DOIArticle
http://link.springer.com/article/10.1007%2Fs003480050094PublisherArticle
Additional Information:© 1997 Springer-Verlag. Received: 15 August 1996; Accepted: 12 November 1996. This work was supported by a grant from the National Science Foundation (NSF Contract MSM 88-20182). Both authors would like to thank Professor Mysels for his enthusiastic support of soap-film efforts in our group.
Group:GALCIT
Funders:
Funding AgencyGrant Number
NSFMSM 88-20182
Issue or Number:2
Record Number:CaltechAUTHORS:20130912-093505922
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20130912-093505922
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:41277
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:12 Sep 2013 23:07
Last Modified:03 Oct 2019 05:47

Repository Staff Only: item control page