Onset of convection with temperature- and depth-dependent viscosity
نویسندگان
چکیده
[1] We derive a scaling law for the onset of convection in an incompressible fluid cooled from above with temperatureand depth-dependent viscosity, on the basis of 2-D numerical simulation. Rayleigh numbers up to 10 are considered. The activation energy is varied from 0 to 200 kJ mol , and a variation of up to 10 is considered in depth-dependent reference viscosity. Our scaling law is shown to be able to handle a variety of buoyancy distributions, including highly non-Gaussian and multimodal distributions, with a tightly constrained critical Rayleigh number.
منابع مشابه
Global Stability for Thermal Convection in a Couple Stress Fluid Saturating a Porous Medium with Temperature-Pressure Dependent Viscosity: Galerkin Method
A global nonlinear stability analysis is performed for a couple-stress fluid layer heated from below saturating a porous medium with temperature-pressure dependent viscosity for different conducting boundary systems. Here, the global nonlinear stability threshold for convection is exactly the same as the linear instability boundary. This optimal result is important because it shows that lineari...
متن کاملEffects of a temperature-dependent viscosity on thermal convection in binary mixtures.
We investigate the effect of a temperature-dependent viscosity on the onset of thermal convection in a horizontal layer of a binary fluid mixture that is heated from below. For an exponential temperature dependence of the viscosity, we find, in binary mixtures as a function of a positive separation ratio ψ and beyond a certain viscosity contrast, a discontinuous transition between two stationar...
متن کاملLow-degree mantle convection with strongly temperature- and depth-dependent viscosity in a three-dimensional spherical shell
A series of numerical simulations of thermal convection of Boussinesq fluid with infinite Prandtl number, with Rayleigh number 10, and with the strongly temperatureand depthdependent viscosity in a three-dimensional spherical shell is carried out to study the mantle convection of singleplate terrestrial planets like Venus or Mars without an Earth-like plate tectonics. The strongly temperature-d...
متن کاملCasson Fluid Flow with Variable Viscosity and Thermal Conductivity along Exponentially Stretching Sheet Embedded in a Thermally Stratified Medium with Exponentially Heat Generation
The motion of temperature dependent viscosity and thermal conductivity of steady incompressible laminar free convective (MHD) non-Newtonian Casson fluid flow over an exponentially stretching surface embedded in a thermally stratified medium are investigated. It is assumed that natural convection is induced by buoyancy and exponentially decaying internal heat generation across the space. The dim...
متن کاملEffect of slip and variable thermal boundary conditions on hydromagnetic mixed convection flow and heat transfer from a non-linearly stretching surface
The effect of partial slip and temperature dependent fluid properties on the MHD mixed convection flow from a heated, non-linearly stretching surface in the presence of radiation and non-uniform internal heat generation/absorption is investigated. The velocity of the stretching surface was assumed to vary according to power-law form. Thermal transport is analyzed for two types of non-isothermal...
متن کامل