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Numerical simulations studies of the convective instability onset in a supercritical fluid
Numerical simulation studies in 2D with the addition of noise are reported
for the convection of a supercritical fluid,3He, in a Rayleigh-Be'nard cell
where the fluid parameters and cell height L are the same as in published
laboratory experiments. The noise addition is to accelerate the instability
onset after starting the heat flow across the fluid, so as to bring simulations
into better agreement with experimental observations. Homogeneous temperature
noise and spatial lateral periodic temperature variations in the top plate were
programmed into the simulations. A speed-up in the instability onset was
obtained, which was most effective through the spatial temperature variations
with a period of 2L, close to the wavelength of a pair of convections rolls.
For a small amplitude of 0.5 microK, this perturbation gave a semiquantitative
agreement with experimental observations. Results for various noise amplitudes
are presented and discussed in relation to predictions by El Khouri and
Carle`s.Comment: 6 pages (2-column format) 4 figures, Proceedings of NASA2004
workshop, Solvang,C
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