A simple extensional viscometer

T. Sridhar, R. K. Gupta

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19 Citations (Scopus)


An extensional viscometer is described in which the liquid filament leaving a capillary is subjected to a stretching deformation. In order to keep the flow rate through the capillary unaltered upon inception of stretching, the pressure head at the capillary entrance has to be reduced by an amount equal to the extensional viscoelastic stress at the capillary exit. This affords a simple means of measuring small fluid forces such as those that occur in the stretching of dilute polymer solutions. Since stretch rates can be obtained from a knowledge of the mass flow rate and the filament diameter profile, extensional viscosities can be computed. The efficacy of the technique is demonstrated by obtaining the anticipated results for Newtonian liquids.

Original languageEnglish
Pages (from-to)207-209
Number of pages3
JournalRheologica Acta
Issue number2
Publication statusPublished - 1 Mar 1985


  • Dilute polymer solution
  • extensional viscometer
  • extensional viscosity
  • stretching flow

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