Related Experiment Video
Updated: Jun 8, 2026

Measuring Material Microstructure Under Flow Using 1-2 Plane Flow-Small Angle Neutron Scattering
Published on: February 6, 2014
Direct observation of flow-concentration coupling in a shear-banding fluid
Matthew E Helgeson1, Lionel Porcar, Carlos Lopez-Barron
1Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge Massachusetts 02139, USA.
Abstract:
We present the first direct evidence of flow-concentration coupling in a shear-banding fluid using the first measurements of scanning narrow-aperture flow ultrasmall-angle neutron scattering. Transmission measurements in the flow-gradient shear plane determine the spatial concentration profile of the material. Shear banding in a model fluid composed of wormlike micelles near an equilibrium isotropic-nematic transition is shown to be concomitant with shear-induced demixing, providing new insight into the nonequilibrium phase behavior of the fluid. The new experimental approach and analysis apply generally to any fluid, and will enable more rigorous testing of theories for shear-banding and shear-induced phase separation.
Related Concept Videos
Couette Flow
Steady, Laminar Flow Between Parallel Plates
Rapidly Varying Flow
Capillarity in Fluid
Surface tension is crucial to capillarity. It results from cohesive forces between liquid molecules at the liquid-air boundary, forming a skin that resists external forces. When the capillary tube...
Steady Flow of a Fluid Stream
During this process, the momentum of the fluid within the control volume remains constant over the time interval dt. By applying the...
Newtonian Fluid: Problem Solving
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...

