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Turbulence modelling for deep ocean radionuclide disposal
Author(s) -
Onishi Yasuo,
Trent Donald S.
Publication year - 1992
Publication title -
international journal for numerical methods in fluids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 112
eISSN - 1097-0363
pISSN - 0271-2091
DOI - 10.1002/fld.1650150910
Subject(s) - turbulence , turbulence modeling , turbulence kinetic energy , tempest , viscosity , radionuclide , geology , sediment , deep sea , vortex , mechanics , large eddy simulation , kinetic energy , meteorology , physics , thermodynamics , nuclear physics , oceanography , classical mechanics , geomorphology , art , art history
In this study the adequacy of the k ‐ϵ turbulence model and the feasibility of the three‐dimensional hydrodynamic‐transport models TEMPEST and FLESCOT for deep ocean radionuclide disposal assessment were evaluated qualitatively. TEMPEST and FLESCOT were applied to a hypothetical, two‐dimensional, deep ocean case with and without stratifications. TEMPEST with the k ‐ϵ model was applied to obtain quasi‐steady state eddy viscosity distributions. With calculated eddy viscosity distributions as part of the input, FLESCOT then calculated distributions of velocity, water temperature, sediment and the dissolved and sediment‐sorbed radionuclide, assuming that the radionuclide was disposed on the ocean bottom. Results revealed that the computed eddy viscosity increased almost linearly with vertical distance near the ocean bottom, then rapidly decreased towards a molecular viscosity value when the vertical gradient of the velocity distribution became very small. The results also demonstrate the importance of the density gradient to suppress the turbulent kinetic energy production, resulting in reduced eddy viscosity, producing the maximum computed eddy viscosity of 0·2 Pa s, which compares well with the reported value of 0·07 Pa s in the deep ocean. Thus the k ‐ϵ turbulence model appears to be qualitatively applicable to the deep ocean environment.