An optical fiber based interferometer to measure velocity profiles in sheared complex fluids

Abstract

We describe an optical fiber based interferometer to measure velocity profiles in sheared complex fluids using Dynamic Light Scattering (DLS). After a review of the theoretical problem of DLS under shear, a detailed description of the setup is given. We outline the various experimental difficulties induced by refraction when using a Couette cell. We also show that homodyne DLS is not well suited to measure quantitative velocity profiles in narrow-gap Couette geometries. On the other hand, the heterodyne technique allows us to determine the velocity field inside the gap of a Couette cell. All the technical features of the setup, namely its spatial resolution ($\approx 50$--$100\mu$m) and its temporal resolution ($\approx 1$ s per point, $\approx 1$ min per profile) are discussed, as well as the calibration procedure with a Newtonian fluid. As briefly shown on oil-in-water emulsions, such a setup permits one to record both velocity profiles and rheological data simultaneously

13 pages, 16 figures, Submitted to Eur. Phys. J. AP

References in corpus (9)

• Rheology of Soft Glassy Materials
• Elastic turbulence in a polymer solution flow
• Deformation and flow of a two-dimensional foam under continuous shear
• Rejuvenation and overaging in a colloidal glass under shear
• Towards local rheology of emulsions under Couette flow using Dynamic Light Scattering
• Chaotic Dynamics in Shear-thickening Surfactant Solutions
• Rheological Chaos in a Scalar Shear-Thickening Model
• Dynamical behavior of a complex fluid near an out-of-equilibrium transition: approaching simple rheological chaos
• Dynamics of Entangled Polymeric Fluids in Two-roll Mill studied via Dynamic Light Scattering and Two-color flow Birefringence. I. Steady flow

Cited by in corpus (16)

• Yield Stress Materials in Soft Condensed Matter
• Velocity profiles in shear-banding wormlike micelles
• Recent experimental probes of shear banding
• High-frequency ultrasonic speckle velocimetry in sheared complex fluids
• Wall slip and flow of concentrated hard-sphere colloidal suspensions
• Slip and flow of hard-sphere colloidal glasses
• Shear-induced transitions and instabilities in surfactant wormlike micelles
• Towards local rheology of emulsions under Couette flow using Dynamic Light Scattering
• Shear-banding in a lyotropic lamellar phase, Part 1: Time-averaged velocity profiles
• Ultrafast ultrasonic imaging coupled to rheometry: principle and illustration
• Dynamics in shear flow studied by X-ray Photon Correlation Spectroscopy
• Shear-banding in a lyotropic lamellar phase, Part 2: Temporal fluctuations
• Local Oscillatory Rheology from Echography
• A novel setup coupling space-resolved dynamic light scattering and rheometetry unveils the heterogeneous flow field and non-affine dynamics in startup shear of a gel
• Quantitative imaging of concentrated suspensions under flow
• Quantitative imaging of colloidal flows