Mechanical & Industrial Engineering

Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/33

The mission of the Mechanical & Industrial Engineering Department is to serve the State of Montana, the region, and the nation by providing outstanding leadership and contributions in knowledge discovery, student learning, innovation and entrepreneurship, and service to community and profession.

Browse

Filters

20201

Settings

Author: search.filters.author.Al-kaby, Rehab N.search.filters.applied.f.department: search.filters.department.Chemical & Biological Engineering.

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Characterization of velocity fluctuations and the transition from transient to steady state shear banding with and without pre-shear in a wormlike micelle solution under shear startup by Rheo-NMR
    (2020-04) Al-kaby, Rehab N.; Codd, Sarah L.; Seymour, Joseph D.; Brown, Jennifer R.
    Rheo-NMR velocimetry was used to study shear banding of a 6 wt.% cetylpyridinium chloride (CPCl) worm-like micelle solution under shear startup conditions with and without pre-shear. 1D velocity profiles across the fluid gap of a concentric cylinder Couette shear cell were measured every 1 s following shear startup for four different applied shear rates within the stress plateau. Fitting of the velocity profiles allowed calculation of the shear banding characteristics (shear rates in the high and low shear band, the interface position and apparent slip at the inner rotating wall) as the flow transitioned from transient to steady state regimes. Characteristic timescales to reach steady state were obtained and found to be similar for all shear banding characteristics. Timescales decreased with increasing applied shear rate. Large temporal fluctuations with time were also observed and Fourier transform of the time and velocity autocorrelation functions quantified the fluctuation frequencies. Frequencies corresponded to the elastically driven hydrodynamic instabilities, i.e. vortices, that are known to occur in the unstable high shear band and were dependent upon both applied shear rate and the pre-shear protocol.
Copyright (c) 2002-2022, LYRASIS. All rights reserved.