"When an elastic-plastic solid is accelerated by a fluid of lower density, Rayleigh-Taylor instability (RTI) is observed, and the instability is mitigated by the material's mechanical strength, initial conditions, and the acceleration that drives the instability. Such instances of RTI are observed in supernovas, explosive welding, and inertial confinement fusion. In contrast to Newtonian fluids, experimental study of RTI in accelerated solids is traditionally hindered by difficulty to measure material properties and exceedingly small time scales. An understanding of the role initial conditions and material properties have on the growth of RTI will lead to better control of the instability.
We present the results for a series of experiments to study the effect of amplitude and wavelength on RT instability with an elastic-plastic solid. A novel rotating wheel RT experiment that uses centrifugal forces to accelerate the two-material interface is used for this purpose. The experiment consists of a container filled with air and mayonnaise, a non-Newtonian emulsion, with an initial perturbation between the two materials. Single mode perturbations of various amplitudes and wavelength were analyzed and results found the instability required for acceleration was inversely proportional to both initial amplitude and wavelength. Three-dimensional (3D) interfaces were found to be more stable than two-dimensional (2D) interfaces. Elastic and plastic peak amplitude responses were observed for stable interfaces using a variable acceleration profile where the test section was first accelerated to slightly below the critical acceleration and then decelerated at the same rate. This exercise allowed for verification of the elastic-plastic (EP) transition process before instability was reached"--Abstract, page iii.
Armaly, B. F. (Bassem F.)
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
Los Alamos National Laboratory
National Science Foundation (U.S.)
Missouri University of Science and Technology
xii, 106 pages
© 2013 Pamela Susan Roach, All rights reserved.
Thesis - Restricted Access
Library of Congress Subject Headings
Computational fluid dynamics
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Roach, Pamela Susan, "Effects of initial conditions on Rayleigh-Taylor instability using elastic-plastic materials" (2013). Masters Theses. 7583.
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