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Bluff Body Wake Stability Enhancement by Mean of Non-Isothermal Blowing

Mathelin L., Bataille F.

Machine Dynamics Research

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2011

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Vol. 35, No. 1

108-122

EN

The influence of blowing or suction from the surface of a porous circular cylinder in crossflow onto the dynamics of its near wake is numerically studied for flows close to the onset of the wake vortex shedding regime at a Reynolds number of 49. Two cases are considered: the blowing may be at the same temperature as the mainstream fluid or at a lower temperature. The latter case is mainly motivated by arguments of thermal protection of the cylinder from a hot incident flow. Local and global instability growth rates are investigated under the effect of different blowing locations and temperatures. It is shown that both blowing and suction have a dramatic impact on the absolutely unstable region, thus affecting the wakr behavior, eventually leading to the suppression of vortex shedding.

2

Free convective heat and mass transfer flow over a non-isothermal stretching sheet with added heat source and thermal diffusion in a saturated porous medium

Pravin V. K., Rajagopal K., Veena P. H., Umesh K. S.

International Journal of Applied Mechanics and Engineering

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2011

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Vol. 16, no 1

177-194

EN

The present paper deals with the study of MHD free convection and mass transfer flow of an incompressible viscous fluid past a continuously moving non-isothermal infinite vertical sheet in non-Darcy porous media in the presence of large suction under the influence of uniform magnetic field considering heat source and thermal diffusion with viscous dissipation, inertia term and stress work. Introducing the usual similarity transformations, the equations of momentum, energy and concentration are made linear. To obtain the solution of the problem, ordinary differential equations are solved analytically. The effects of various physical parameters such as the magnetic parameter, permeability parameter, inertia parameter, suction/blowing parameter on heat transfer characteristics are analysed. One of the important findings of our study is that of increasing the value of the inertia parameter k3 decreases the velocity profile and to increase the temperature profile.

3

Heat and mass transfer flow with variable thermal conductivity and variable mass diffusivity in an MHD visco-elastic fluid over a non-isothermal stretching sheet

Veena P. H., Pravin V. K., Shahjahan S. M.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 2

515-541

EN

In this paper we present a mathematical analysis of heat and mass transfer phenomena in a visco-elastic fluid flow over a non-isothermal stretching sheet with variable thermal conductivity and variable mass diffusivity. Similarity transformation are used to convert highly non-linear partial differential equations into ordinary differential equations. Several closed form analytical solutions for non-dimensional temperature, concentration, heat flux and mass flux are obtained in the form of confluent hypergeometric functions for two different types of the boundary conditions, namely: (i) wall with prescribed second-order power law temperature and second-order power law concentration (PST) and (ii)wall with prescribed second-order power law heat flux and second-order power law mass flux (PHF). The effect of various physical parameters such as the suction/blowing parameter , heat source/sink parameter [...], Prandtl number Pr, Schmidt number Sc, visco-elastic parameter and permeability parameter on the temperature and concentration profiles are analyzed.