Assessment of errors induced by the anomalous dispersion of high frequency shear waves in rheometrical measurements on gelling systems

Jones, R.A.; Ravji, S.; Hawkins, K.; Al-Hussany, A.; Williams, P.R.; Williams, R.L.

Abstract

The principal objectives of the work reported in this paper were two-fold. Firstly, to assess, by means of the numerical simulation of transverse wave propagation within a linear viscoelastic medium, the degree to which wavegroup propagation involving a finite frequency interval (2Δω) corresponds to an ‘ideal’ beat (i.e. one for which 2Δω → 0). Secondly, to compare the results of shear wave propagation measurements with predictions based on a rheometrical theory, which describes the gelation of materials in terms of their wave dispersion characteristics. The results of the numerical simulations indicate that for a sufficiently small value of the frequency interval Δω/ω, the nodal and anti-nodal regions of the amplitude modulation envelope of wavegroups propagating within a critical-gel may be defined with sufficient accuracy to permit calculation of the corresponding value of the group velocity U. The results of high frequency shear wave dispersion measurements made on a system known to display critical-gel behaviour provide encouraging agreement with theory and the results of the simulations.

Citation

Jones, R., Ravji, S., Hawkins, K., Al-Hussany, A., Williams, P., & Williams, R. (2004). Assessment of errors induced by the anomalous dispersion of high frequency shear waves in rheometrical measurements on gelling systems. Journal of Non-Newtonian Fluid Mechanics, 124(1-3), 11-24. https://doi.org/10.1016/j.jnnfm.2004.07.007

• Journal Article Type: Article
• Acceptance Date: Dec 1, 2004
• Online Publication Date: Nov 11, 2004
• Publication Date: 2004-12
• Deposit Date: Aug 1, 2016
• Journal: Journal of Non-Newtonian Fluid Mechanics
• Print ISSN: 0377-0257
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 124
• Issue: 1-3
• Pages: 11-24
• DOI: https://doi.org/10.1016/j.jnnfm.2004.07.007
• Keywords: Shear waves, Wave dispersion, Gel-point,
• Public URL: http://researchrepository.napier.ac.uk/Output/320698