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Crystal growth and fluid mechanics problems in directional solidificationBroadly speaking, our efforts have been concentrated in two aspects of directional solidification: (A) a more complete theoretical understanding of convection effects in a Bridgman apparatus; and (B) a clear understanding of scalings of various features of dendritic crystal growth in the sensitive limit of small capillary effects. For studies that fall within class A, the principal objectives are as follows: (A1) Derive analytical formulas for segregation, interfacial shape and fluid velocities in mathematically amenable asymptotic limits. (A2) Numerically verify and extend asymptotic results to other ranges of parameter space with a view to a broader physical understanding of the general trends. With respect to studies that fall within class B, the principal objectives include answering the following questions about dendritic crystal growth: (B1) Are there unsteady dendrite solutions in 2-D to the completely nonlinear time evolving equations in the small surface tension limit with only a locally steady tip region with well defined tip radius and velocity? Is anisotropy in surface tension necessary for the existence of such solutions as it is for a true steady state needle crystal? How does the size of such a local region depend on capillary effects, anisotropy and undercooling? (B2) How do the different control parameters affect the nonlinear amplification of tip noise and dendritic side branch coarsening?
Document ID
19950008136
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Tanveer, Saleh
(Ohio State Univ. Columbus, OH, United States)
Baker, Gregory R.
(Ohio State Univ. Columbus, OH, United States)
Foster, Michael R.
(Ohio State Univ. Columbus, OH, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1994
Publication Information
Publication: NASA. Lewis Research Center, Second Microgravity Fluid Physics Conference
Subject Category
Solid-State Physics
Accession Number
95N14550
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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