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The extensional rheology of non-Newtonian materialsIt has been proposed to measure the extensional viscosity function of a non-Newtonian polymer solution in a reduced gravity environment as part of the Advanced Fluid Module. In ground-based extensional measurements, the no-sip boundary condition at solid-fluid interfaces always result in appreciable shear gradients in the test fluid; however the removal of gravitational body forces permits controlled extensional deformation of containerless test samples and the first unambiguous measurements of this kind. Imperative to successful implementation of this experiment is the generation and subsequent deformation of a stable cylindrical column of test fluid. A study of the generation and deformation of liquid bridges demonstrates that Newtonian liquid bridges undergo capillary breakup as anticipated when stretched beyond a critical aspect ratio; non-Newtonian liquid bridges, however, are stabilized by the strain-hardening phenomenon exhibited by these materials. Numerical simulations of Newtonian breakup are compared with experimental results, and show that previous ground-based attempts at measuring the extensional viscosity of Newtonian fluids are of limited accuracy.
Document ID
19950008155
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Spiegelberg, Stephen H.
(Harvard Univ. Cambridge, MA, United States)
Gaudet, Samuel
(Harvard Univ. Cambridge, MA, United States)
Mckinley, Gareth H.
(Harvard Univ. Cambridge, MA, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1994
Publication Information
Publication: NASA. Lewis Research Center, Second Microgravity Fluid Physics Conference
Subject Category
Fluid Mechanics And Heat Transfer
Accession Number
95N14569
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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