Dr. Matthew Harvey and Dr. Tom Waigh based at the Photon Science Institute of the University of Manchester have built a new device that allows the velocity profiles of opaque materials to be measured as they are sheared. They have used it to study a range of soft matter systems under flow including colloids (polystyrene spheres in water), polyelectrolytes (polyacrylamide), margarine and plant cell suspensions (tomato ketchup). Unusual fluid mechanics/viscoelastic phenomena have been measured such as wall slip and shear banding. The apparatus uses optical fibres. It is built around a Michelson interferometer and functions at infra-red wavelengths.

For more detail see the abstract with figures.

Reference: M.Harvey, T.A.Waigh, "Optical coherence tomography velocimetry in controlled shear flow", Physical Review E, 2011, 83, 031502.