The effect of temperature-dependent viscosity and thermal conductivity on the onset of compressible convection
| Autor: | Abrar A. Ali, L. J. Silvers |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Convection
Materials science Convective heat transfer Computational Mechanics Astronomy and Astrophysics Temperature dependent viscosity Mechanics 01 natural sciences Compressible flow 010305 fluids & plasmas Physics::Fluid Dynamics Geophysics Thermal conductivity Geochemistry and Petrology Mechanics of Materials 0103 physical sciences Compressibility Astrophysics::Solar and Stellar Astrophysics Magnetohydrodynamics 010303 astronomy & astrophysics QC Physics::Atmospheric and Oceanic Physics Linear equation |
| Zdroj: | Geophysical & Astrophysical Fluid Dynamics. 115:207-220 |
| ISSN: | 1029-0419 0309-1929 |
| Popis: | The linear equations of thermal convection in a compressible fluid with non-constant transport coefficients are derived. The criterion for the onset of convection is established, based on linear stability analysis, for a range of different temperature-dependent profiles of thermal conductivity and viscosity. Temperature-dependent transport coefficients are shown to lead to a more complex behaviour than their constant counterparts, and modifies the stability condition of the fluid. When the Rayleigh number is defined in terms of the mid-layer physical properties and the temperature gradient at the top is held constant, increasing the temperature-dependence of thermal conductivity is found to raise the critical Rayleigh number dramatically, as the convective disturbance is then concentrated mainly at the top of the layer. In contrast, for viscosity a more subtle effect on stability is identified. |
| Databáze: | OpenAIRE |
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