THE DAMPING OF CAPILLARY WAVES AT THE AIR/ WATER INTERFACE BY NATURALLY OCCURRING SURFACE-ACTIVE MATERIAL.
Abstract
The damping of capillary waves was measured on fresh sea water, sampled from the Bay of Panama under various oceanographic conditions. The collected water contained varying quantities of surface-active organic materials capable of adsorbing at the air/water interface and altering the surface properties. Agitation, thermal currents, and bubbling were studied as mechanisms for the transport of film-forming material from the bulk water to the surface. Large increases in the rate of film accumulation occurred when these mechanisms were applied. Simultaneous measurements of damping coefficient and film pressure indicated that wave damping commenced at a film pressure of a few tenths of 1 dyne/cm and increased to a maximum value of from 0.39 to 0.44/cm in the neighborhood of 1 dyne/cm. As the film pressure was increased further by compression of the surface film, the damping coefficient decreased to a value of about 0.26/cm and became constant when the film pressure had reached 2 dynes/cm. It was postulated that a portion of the wave energy loss was due to a viscous drag of the associated chains of water molecules which were bonded to the molecules of the adsorbed surface film. The drag occurs when the molecules are forced into movement as a result of the alternating compression and expansions of the surface caused by the passing progressive waves. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 19, 1965
- Accession Number
- AD0624933
Entities
People
- W. D. Garrett
Organizations
- United States Naval Research Laboratory