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A new method for surface shear viscosity measurements: Decay of surface motions at a rotated gas—liquid interface

1981; Elsevier BV; Volume: 79; Issue: 1 Linguagem: Inglês

10.1016/0021-9797(81)90044-8

1095-7103

R.D. Krieg, Jieun Son, Raymond W. Flumerfelt,

Characterization and Applications of Magnetic Nanoparticles

The theoretical basis for a new method for the measurement of the surface shear viscosity of a Newtonian liquid—gas interface is presented. The method involves the observation of decaying surface motions of a cup of liquid following cessation of steady rigid body rotation. Its basis stems from the sensitivity of the resulting angular displacements of surface elements to the shear properties of the interface. The method is most sensitive when the ratio of liquid height to cup radius is approximately 1 and when the observed surface elements are at radial positions somewhat removed from the cup walls. Series and graphical solutions are provided for determining the surface shear viscosity from measurements of original cup angular speed, cup geometry, surface particle angular displacement, and bulk fluid properties. Finally, experimental results are reported on water/air and oil/air systems with negligibly small surface shear viscosity effects. Angular displacement measurements show good agreement with those predicted theoretically.