Boundary-layer thickness and instabilities in Bénard convection of a liquid with a temperature-dependent viscosity
نویسندگان
چکیده
New and published experimental measurements of spatial and temporal aspects of variable-viscosity convection are compared with boundary layer models. Viscosity m is assumed to decrease with increasing temperature T so that convection occurs beneath a relatively stagnant layer. Of particular interest to applications involving asymptotically large viscosity variations, is the result that both the temperature difference across the hot thermal boundary layer and the frequency of thermal formation scale with the rheological temperature scale 2(d log m/dT). Measurements indicate that for large Rayleigh numbers, viscosity varies by less than a factor of '37 across the actively convecting region. © 2001 American Institute of Physics. @DOI: 10.1063/1.1345719#
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 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 کاملChemical Reaction Effects on Bio-Convection Nanofluid flow between two Parallel Plates in Rotating System with Variable Viscosity: A Numerical Study
In the present work, a mathematical model is developed and analyzed to study the influence of nanoparticle concentration through Brownian motion and thermophoresis diffusion. The governing system of PDEs is transformed into a coupled non-linear ODEs by using suitable variables. The converted equations are then solved by using robust shooting method with the help of MATLAB (bvp4c). The impacts o...
متن کاملInsight into the Boundary Layer Flows of Free Convection and Heat Transfer of Nanofluids over a Vertical Plate using Multi-Step Differential Transformation Method
This paper presents an insight into the boundary layer of free convection and heat transfer of nanofluids over a vertical plate at very low and high Prandtl number. Suitable similarity variables are used to convert the governing systems of nonlinear partial differential equations of the flow and heat transfer to systems of nonlinear ordinary differential equations which are solved using multi-s...
متن کامل