"Characterizing molecular mixing in Rayleigh-Taylor instability (RTI) driven flows where the density and velocity fields are coupled is essential for developing exacting predictive models. Sensitivity of the Rayleigh Taylor mixing layer to initial conditions is a topic that is being explored extensively in interests of accurate turbulent mix model development and its direct consequence in various applications like design of inertial confinement fuel capsule and atmospheric modeling. As part of the current work, an experimental investigation of the effect of initial conditions on molecular mixing in a low Atwood number(~7.5 x 10⁻⁴), high Schmidt number(~1000), RTI driven mixing layer is undertaken. An experimental facility for observing the evolution of an RTI driven mixing layer to a buoyancy Reynolds number of ~10000 was developed. Diagnostics for measuring volume fraction evolution through passive scalar (Nigrosine) estimates and mixture fraction evolution through reactive scalar (Phenolphthalein) measurements were calibrated and established. The initial perturbations at the interface were modeled from the passive scalar runs and validated using an Implicit Large Eddy simulation (ILES). Molecular mixing parameter estimates were calculated by combining the results from the passive scalar and reactive scalar runs. An examination of molecular mixing measurements vis-a-vis variations in initial conditions has revealed that the low wave number loading of the initial density perturbation spectrum has a profound effect on molecular mixing in the mixing layer. The variation was observed in both local and global mixing with possible implications pointing to the delay in mixing transition"--Abstract, page iii.
Armaly, B. F. (Bassem F.)
Isaac, Kakkattukuzhy M.
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
National Science Foundation (U.S.)
University of Missouri Research Board
Missouri University of Science and Technology
ix, 104 pages
© 2011 Lakshmi Ayyappa Raghu Mutnuri, All rights reserved.
Thesis - Open Access
Computational fluid dynamics
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Mutnuri, Lakshmi Ayyappa Raghu, "Effect of initial conditions on molecular mixing in a high Schmidt-number Rayleigh-Taylor mixing layer" (2011). Masters Theses. 7142.