There are two coupled objectives for this study of buoyancy-driven turbulence. The first
objective is to determine if the development of a Rayleigh-Taylor (RT) mixing layer can be
manipulated experimentally by altering the initial condition of the experiment. The second
objective is to evaluate the performance of the Besnard, Harlow, and Rauenzahn (BHR)
turbulent transport model when initialized with experimentally measured initial conditions. An
existing statistically steady water channel facility at Texas A&M University and existing
experimental diagnostics developed for this facility have been used to measure the turbulent
quantities of buoyancy-driven turbulence. A stationary, bi-planar grid with a high solidity ratio,
σ, has been placed immediately downstream of the termination of the splitter plate, perpendicular
to the flow direction, to generate a turbulent initial condition. The self-similar growth parameter,
α , for the RT mixing layer has been measured using a visualization technique to determine if
the initial conditions affect the development of the RT mixing layer. The self-similar growth
parameter, α , decreased from a value of 0.072 ± 0.0003 with the fine grid to values of 0.063 ±
0.0003 and 0.060 ± 0.0003 with the medium and coarse grids, respectively. With the results
from the first objective, a unique opportunity arose to evaluate the performance of the variable
density, RANS-type, BHR turbulent transport model. Measurements of velocity statistics necessary to initialize the model accurately have been obtained using particle image velocimetry
(PIV). The performance of the BHR model was evaluated through comparison of the
experimentally measured and BHR modeled self-similar growth parameter, α , from the
penetration height of the bubbles/spikes and the self-similar growth parameter, K α , of the
turbulent kinetic energy at the centerline of the low Atwood RT driven turbulent mixing layer.
When initialized with the experimentally measured initial conditions, the BHR model did agree
with the experimental measurements of the penetration height growth parameter, α , as well as
the centerline turbulent kinetic energy growth parameter, K α , in the self-similar portion of the
flow.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-3010 |
| Date | 15 May 2009 |
| Creators | Peart, Freeman Michael |
| Contributors | Andrews, Malcolm J. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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