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Soil Thermal Diffusivity Determination from Overspecification of Boundary Data
Author(s) -
Singh S. R.,
Sinha B. K.
Publication year - 1977
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1977.03615995004100050002x
Subject(s) - thermal diffusivity , boundary (topology) , thermal conduction , boundary value problem , thermal , dirichlet boundary condition , mathematics , mechanics , temperature gradient , mathematical analysis , materials science , thermodynamics , physics , meteorology
The heat conduction equation has been solved for evaluating thermal diffusivity of soils by overspecifying the usual boundary conditions in terms of the thermal gradient at the boundary surface. Solutions have been obtained for different Dirichlet‐type boundary conditions describing the boundary temperature. These were (i) linearly rising/falling, (ii) exponentially rising, (iii) exponentially falling, and (iv) sinusoidal. The thermal gradient in the soil profile was evaluated using a cubic spline. Field data were analyzed firstly by representing the surface temperature as linearly rising and secondly as sinusoidal. More consistent results were obtained with the help of the first approximation which represented the boundary data closely. This shows that a close approximation of boundary condition by an appropriate function is essential to get reliable values of the thermal diffusivity.