Relaxation behavior of dense suspensions
Name
1197973764-MIT.pdf
Size
1.04 MB
Format
Adobe PDF
Checksum (MD5)
50b680a9815548ff459164f09ba2a876
Author(s)
Griese, Andrew Herman.
Advisor(s)
Irmgard Bischofberger.
Date Issued
2020
Publisher
Massachusetts Institute of Technology
Abstract
Dense suspensions of solid particles in Newtonian fluids exhibit a variety of non-Newtonian behaviors depending on the shear stress applied to the suspension and the particle mass fraction ([mathematical symbol]m). Suspensions at sufficiently high fm shear-thicken dramatically and eventually shear jam, showing behaviors typified by solids. But, little is known about how dense suspensions relax out of this stressed rheological state. To understand the relaxation behavior of a cornstarch/water dense suspension, samples are prepared at different fm, in the range that shows dramatic shear thickening, between 54.5% and 58.5% cornstarch. Each sample is formed into drops and kept in the stressed state through dynamic shearing using a B&K permanent magnet shaker, then allowed to relax. We show that dense suspensions relax with two distinct timescales. A short timescale that is independent of [mathematical symbol]m, denoting the settling of the drop onto the flat surface, and a longer timescale that is governed by the viscosity of the dense suspension and increases as [mathematical symbol]m increases above 55.75%. Our work provides an understanding of how a dense suspension relaxes out of a shear-thickened state.
Description
Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020
Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 16-17).
Subjects
Mechanical Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
Terms of Use
MIT theses may be protected by copyright. Please reuse MIT thesis content according to the MIT Libraries Permissions Policy, which is available through the URL provided.
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