Steady flows of a laterally heated ferrofluid layer: Influence of inclined strong magnetic field and gravity level

in Physics of Fluids (2006), 18(9),

A horizontal ferrofluid layer is submitted to a lateral heating and to a strong oblique magnetic field. The problem, combining the momentum and heat balance equations with the Maxwell equations ... [more ▼]

A horizontal ferrofluid layer is submitted to a lateral heating and to a strong oblique magnetic field. The problem, combining the momentum and heat balance equations with the Maxwell equations, introduces two Rayleigh numbers, Ra the gravitational one and Ram the magnetic one, to represent the buoyancy and the Kelvin forces, which induce motion, versus the momentum viscous diffusion and heat diffusion. Whatever the inclination of the magnetic field, the steady solution of the problem is presented as a power series of a small parameter epsilon(H) measuring the ratio of variation of the magnetization across the layer divided by the magnitude of the external imposed field. For cases of physical relevance, comparisons between analytical and numerical studies have lead to a major statement: in the strong field region (epsilon(H)<< 1) the zero order solution is the product of the Birikh solution that corresponds to the usual Newtonian fluid submitted to a lateral gradient, multiplied by a modulating factor accounting for inclination and both Rayleigh numbers. Physically, this simplified solution is valid for microgravity conditions where the magnetic field competes enough with microgravity effects to invert the laminar flow and thus suppress the motion for two specific values of the inclination angle. (c) 2006 American Institute of Physics. [less ▲]

On the Rayleigh-Marangoni-Benard instability of a Ferrofluid Layer, submitted to a Vertical Magnetic Field

in 2nd International Marangoni Association Congress (2004)

Analyse de stabilité linéaire d'un ferrofluide saturant un milieu poreux en rotation

in congrès français de mécanique (2003)

Linear coupling between the Rayleigh-Bénard instability and rotation for a ferrofluid in a normal magnetic fluid

in The first international conference on applications of porous media (2002)

Coupled capillary and gravity-driven instability in a liquid film overlying a porous layer

in Physical Review E (2001), 64(6, Pt 2), 66304

In this work, we study the problem of onset of thermal convection in a fluid layer overlying a porous layer, the whole system being heated from below. We use Brinkman's model to describe the porous medium ... [more ▼]

In this work, we study the problem of onset of thermal convection in a fluid layer overlying a porous layer, the whole system being heated from below. We use Brinkman's model to describe the porous medium and determine the corresponding linear stability equations. The eigenvalue problem is solved by means of a modified Galerkin method. The behavior of the critical wave number and temperature gradient is discussed in terms of the various parameters of the system. We also emphasize the influence of the boundary conditions at the upper surface of the fluid layer; in particular, we examine the role of a free surface whose surface tension is temperature dependent (Marangoni effect). Comparison with earlier works is also made. [less ▲]

Coupled capillary and gravity-driven instabilities in a bilayer porous liquid system

in 52nd annual meeting of the division of fluid dynamics of the American physical society (1999)