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1

Unsteady MHD natural convective boundary layer flow and heat transfer over a truncated cone in the presence of pressure work

Ajay C. K., Srinivasa A. H.

Journal of Applied Mathematics and Computational Mechanics

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2020

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Vol. 19, nr 1

5--16

EN

The aim of the present paper is to analyse the effect of MHD on unsteady natural convection boundary layer flow and heat transfer over a truncated cone in the presence of pressure work. Suitable transformation is utilized to form a system of coupled non-linear partial differential equations for governing both the flow and heat transfer. These equations have been solved numerically by utilizing an implicit finite difference scheme along with quasilinearization method. Here, the computed numerical results are displayed graphically in terms of the local Nusselt number, skin friction, temperature distribution, and velocity distribution for various values of the magnetic and pressure work parameters along with the fixed Prandtl number

2

Experimental and numerical investigations of natural convection phenomena in a fermentation tank

Klembt Daniel, Meironke Heiko

Journal of Mechanical and Energy Engineering

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2019

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Vol. 3, No 3

235--244

EN

In the context of investigations of real multiphase flows, the university has its own 350 litre fermentation tank with comprehensive acoustic flow and temperature measurement technology for the systematically investigation, of the influence of the fermentation activity, distribution of yeast and occurring convection phenomena. Due to the many problems with the optical (e.g. PIV) and acoustic (e.g. UDV) measurement in a real fermenting fluid the numerical simulation was already used in earlier publications. To validate the numerical models, extensive experimental investigations were carried out which show that the flow in the fermenter is caused only by the reaction products of the yeast and the cooling panels and controls the yeast distribution. In this paper, both the numerical (CFD) and the experimental investigations serve as a starting point to influence the yeast distribution. The described convection flow can only temporarily guarantee the uniform distribution of the yeast in the fermenter until the sedimentation of the yeast at the tank bottom (bottom-fermenting yeast) finally begins. The aim of the investigation is to influence the convection flow in certain zones by targeted cooling or heating of the jackets in such a way that a uniform spatial distribution of the yeast over the entire fermentation process is ensured and thus optimal conditions for its metabolic processes are given. Finally, the numerical simulation is validated with the experimental data.

3

Effect of chemical reaction on mixed convective nanofluid flow on a vertical plate with uniform heat and mass fluxes

Mondal H., Goqo S. P., Sibanda P., De P.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 2

329--342

EN

The purpose of this paper is to consider a two dimensional free convective flow of a nanofluid due to the combined effects of thermal and mass diffusion in the presence of a chemical reaction of first order. The objective of the present investigation is to analyze the free convective flow in the presence of prescribed wall heat flux and mass flux condition. The governing equations of the linear momentum, energy equation and concentration are obtained in a dimensionless form by introducing a suitable group of similarity transformations. The transformed coupled non-linear ordinary differential equations are solved numerically by using appropriate boundary conditions for the various values of physical parameters. Computations are performed for a wide range of values of the various governing flow parameters of the velocity, temperature and species concentration profiles and results are presented graphically. Numerical results for the skin friction coefficient and local Nusselt number are also presented and analyzed in detail. The obtained results are compared with previously published work and are found to be in excellent agreement. The results are a very useful source of information for researchers on the subject of a free convective flow of a nanofluid. This paper illustrates chemical reaction effects on free convective flow of a nanofluid from a vertical plate with uniform heat and mass fluxes.

4

Initial unsteady free convective flow past an infinite vertical plate with radiation and mass transfer effects

Khan A., Solanki R.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 4

931--943

EN

An exact solution and analysis of an initial unsteady two dimensional free convection flow, heat and mass transfer in the presence of thermal radiation along an infinite fixed vertical plate when the plate temperature is instantaneously raised, is presented. The fluid considered is a gray, absorbing emitting radiation but a nonscattering medium. Three cases have been discussed, in particular, namely, (i) when, the plate temperature is instantaneously raised to a higher constant value, (ii) when, the plate temperature varies linearly with time and (iii) when, the plate temperature varies non-linearly with time. A close form general solution for all the cases has been obtained in terms of repeated integrals of error functions. In two particular cases, the solutions in terms of the repeated integrals of error functions have been further simplified to forms containing only error functions. It is observed that for an increase in the radiation parameter N or a decrease in the Grashof number Gr or Gm, there is a fall in the velocity or temperature, but compared to the no radiation case or no diffusing species, there is a rise in the velocity and temperature of the fluid.

5

Hydromagnetic rarefied fluid flow over a wedge in the presence of surface slip and thermal radiation

Das K., Sharma R. P., Duari P. R.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 4

827--837

EN

An analysis is presented to investigate the effects of thermal radiation on a convective slip flow of an electrically conducting slightly rarefied fluid, having temperature dependent fluid properties, over a wedge with a thermal jump at the surface of the boundary in the presence of a transverse magnetic field. The reduced equations are solved numerically using the finite difference code that implements the 3-stage Lobatto IIIa formula for the partitioned Runge-Kutta method. Numerical results for the dimensionless velocity and temperature as well as for the skin friction coefficient and the Nusselt number are presented through graphs and tables for pertinent parameters to show interesting aspects of the solution.

6

Mass transfer effects on an unsteady MHD free convective flow of an incompressible viscous dissipative fluid past an infinite vertical porous plate

Reddy B. P.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 1

143--155

EN

In this paper, a numerical solution of mass transfer effects on an unsteady free convection flow of an incompressible electrically conducting viscous dissipative fluid past an infinite vertical porous plate under the influence of a uniform magnetic field considered normal to the plate has been obtained. The non-dimensional governing equations for this investigation are solved numerically by using the Ritz finite element method. The effects of flow parameters on the velocity, temperature and concentration fields are presented through the graphs and numerical data for the skin-friction, Nusselt and Sherwood numbers are presented in tables and then discussed.

7

Effects of Hall current on unsteady hydromagnetic free convection flow past an impulsively moving vertical plate with Newtonian heating

Seth G. S., Sarkar S., Sharma R.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 1

187--203

EN

An investigation of unsteady hydromagnetic free convection flow of a viscous, incompressible and electrically conducting fluid past an impulsively moving vertical plate with Newtonian surface heating embedded in a porous medium taking into account the effects of Hall current is carried out. The governing partial differential equations are first subjected to the Laplace transformation and then inverted numerically using INVLAP routine of Matlab. The governing partial differential equations are also solved numerically by the Crank-Nicolson implicit finite difference scheme and a comparison has been provided between the two solutions. The numerical solutions for velocity and temperature are plotted graphically whereas the numerical results of skin friction and the Nusselt number are presented in tabular form for various parameters of interest. The present solution in special case is compared with a previously obtained solution and is found to be in excellent agreement.

8

Axisymmetric mixed convective MHD flow over a slender cylinder in the presence of chemically reaction

Prasad K. V., Vaidya H., Vajravelu K., Datti P. S., Umesh V.

International Journal of Applied Mechanics and Engineering

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2016

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Vol. 21, no. 1

121--141

EN

The present analysis is focused on the study of the magnetic effect on coupled heat and mass transfer by mixed convection boundary layer flow over a slender cylinder in the presence of a chemical reaction. The buoyancy effect due to thermal diffusion and species diffusion is investigated. Employing suitable similarity transformations, the governing equations are transformed into a system of coupled non-linear ordinary differential equations and are solved numerically via the implicit, iterative, second order finite difference method. The numerical results obtained are compared with the available results in the literature for some special cases and the results are found to be in excellent agreement. The velocity, temperature, and the concentration profiles are presented graphically and analyzed for several sets of the pertinent parameters. The pooled effect of the thermal and mass Grashof number is to enhance the velocity and is quite the opposite for temperature and the concentration fields.

9

Role of induced magnetic field on transient natural convection flow in a vertical channel: The Riemann sum approximation approach

Jha B. K., Sani I.

International Journal of Applied Mechanics and Engineering

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2015

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Vol. 20, no. 1

65--85

EN

This paper investigates the role of induced magnetic field on a transient natural convection flow of an electrically conducting, incompressible and viscous fluid in a vertical channel formed by two infinite vertical parallel plates. The transient flow formation inside the channel is due to sudden asymmetric heating of Chanel walls. The time dependent momentum, energy and magnetic induction equations are solved semi-analytically using the Laplace transform technique along with the Riemann-sum approximation method. The solutions obtained are validated by comparisons with the closed form solutions obtained for the steady states which hale been derived separately and also by the implicit finite difference method. Graphical results for the temperature, velocity, induced magnetic field, current density, and skin-friction based on the semi-analytical solutions are presented and discussed.

10

Dual solutions for boundary layer flow of moving fluid over a moving surface with power-law surface temperature

Mukhopadhyay S., Gorla R. S. R.

International Journal of Applied Mechanics and Engineering

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2013

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Vol. 18, no. 1

113--124

EN

An analysis of heat transfer for boundary layer forced convective flow past a moving flat surface parallel to a moving stream is presented. The power-law surface temperature at the boundary is prescribed. The surface temperature varying directly (or inversely) with power-law exponent is considered. The similarity solutions for the problem are obtained and the reduced ordinary differential equations are solved numerically. To support the validity of the numerical results, a comparison is made with known results from the open literature for some particular cases of the present study. When the surface and the fluid move in the opposite directions, dual solutions exist.

11

Unsteady convection and mass transfer flow in three dimension over an inclined plate through a porous medium with periodic permeability

Chaudhary D., Jain N. C., Jat. R. N.

International Journal of Applied Mechanics and Engineering

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2011

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Vol. 16, no 4

959-975

EN

A three dimensional unsteady convection flow of a viscous incompressible fluid through a highly porous medium with mass transfer effects bounded by an infinite inclined porous plate is analyzed. Assuming the free stream velocity to be uniform, approximate solutions are obtained and the effects of the following: the magnetic field (M), permeability parameter (K0), thermal Grashof number (Gr), mass Grashof number (Gc), Prandtl number (Pr), Schmidt number (Sc) and angle of inclination ( )on the velocity field, the temperature field, skin friction and the rate of heat transfer are discussed with the help of graphs. It is observed that an increase in K0 increases the skin friction but decreases the Nusselt number near the plate which increases as we move away from the plate whereas increase in M decreases the skin friction as well as the Nusselt number near the plate.

12

Natural convection flow of a third grade fluid in a circular pipe

Ariel P. D.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 2

311-323

EN

The steady, laminar, natural convection flow of a third grade fluid in a vertical circular pipe is investigated when a constant temperature is maintained at the walls of the pipe. The flow is governed by a pair of coupled equations in velocity and temperature fields involving the parameters K, which is the product of the Eckert and Prandtl number, and [...] which is a measure of the third grade fluid parameter. Solutions are obtained (i) by numerical integration of the differential equations governing the flow, and (ii) by seeking a perturbation solution in terms of the parameter K. The results are compared and appropriate conclusions drawn regarding the applicability of the perturbation solution. It is shown that the effect of the third grade fluid parameter is to counteract the influence of the parameter K on the flow.

13

Mixed Convection on a Vertical Flat Plate with Variable Magnetic Field

Dimian M. F., Hadhoda M. Kh.

Mechanics and Mechanical Engineering

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2007

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Vol. 11, nr 1

97-112

EN

The steady laminar incompressible boundary layer mixed convection flow of an electrically conducting fluid on a vertical flat plate in the presence of an applied magnetic field has been studied. The effect of the induced magnetic field has been considered in the analysis. The resulting partial differential equations are transformed into a system of ordinary differential equations which have been solved numerically using shooting method. Two cases are considered here for the buoyancy force: (i) when it acts in the same direction as the forced flow (Tw > T∞), (ii) when it acts in the opposite direction to the forced flow (Tw < T∞). The velocity profiles, temperature profiles, the skin friction on the plate and the rate of heat transfer coeffcient (Nusselt number) are computed and discussed for different values of the magnetic force number β, the thermal buoyancy force ╏, reciprocal of the magnetic Prandtl number α and viscous dissipation parameter (Eckert number) Ec for the two cases.

14

Effect of radiatlon and viscous dissipation on convection flow in a vertical porous channel

Malashetty M. S., Swamy M.

International Journal of Applied Mechanics and Engineering

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2007

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Vol. 12, no 4

1049-1060

EN

The effect of radiation on a combined free and forced convection flow of a Boussinesq fluid through a vertical porous channel with viscous and Darcy dissipation is investigated analytically. The temperature of the walls is assumed to be equal and vary linearly with the height of the wall. Closed form solutions are obtained using a perturbation method valid for smalI values of the Eckert number. The effects of radiation, the porous parameter and Prandtl number on the velocity, temperature, flow rate and rate of heat transfer are presented graphically.

15

Konvektivnih potoki ta jikh vpliv na organihzacihju povitroobmihnu v primihshhennih

Zhelikh V., Shhegljuk T., Jurkevich J.

Zeszyty Naukowe Politechniki Rzeszowskiej. Budownictwo i Inżynieria Środowiska

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2004

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z. 37[211], cz.2

489-494

EN

In this article the results of air distribution of laminar air stream in volume of the module of a technological room are presented.

16

Natural convection flows with variable viscosity, heat and mass diffusion along a vertical plate

Dimian M. F., Hadhoda M. K.

Mechanics and Mechanical Engineering

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2004

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Vol. 7, nr 2

61-76

EN

The aim of this paper is a numerical study of laminar double diffusive free convection viscous flows adjacent to a vertical plate, taking into account the variation of the viscosity and double-diffusive heat and mass transfer with temperature. The governing conservation equations of mass, momentum, energy and chemical species are non-dimensionalized by using appropriate transformations. The resulting equations are solved numerically by using the fourth order Runge-Kutta integration scheme along with the Nachtsheim-Swiger shooting technique. It is noticed that both the velocity and concentration of air are increasing as the parameter Β 2, (the species diffusion parameter) increases, but an opposite effect for the velocity is observed at a certain distance far from the plate. It is also observed that the temperature decreases as the parameter Β 2 increases. The shearing stress at the plate, the local Nusselt number and the local Sherwood number are obtained. The friction coefficient at the plate, of heat and mass transfer at the plate, the momentum, thermal and concentration boundary layers thickness (δ, δ T, δ C) have been estimated for different values of α, Sc and N.

17

Steady laminar water boundary layer flow over a yawed cylinder

Roy S., Saikrishnan P.

International Journal of Applied Mechanics and Engineering

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2004

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Vol. 9, no 4

739-747

EN

The aim of this work is to study the influence of temperature-dependent viscosity and the Prandtl number on the steady non-similar laminar forced convection flow over a yawed infinite circular cylinder starting from the origin of the streamwise coordinate to the point of separation (zero skin friction in the streamwise direction). The results show that the effect of variable viscosity and the Prandtl number is to move the point of separation downstream and the yaw angle has very little effect on the location of the point of separation. The heat transfer rate is found to depend strongly on viscous dissipation, wheras skin frictions are comparatively less affected. In general, the results pertaining to variable fluid properties differ significantly from those of constant fluid properties.

18

Transient free convection flow of dissipative fluid past an infinite vertical porous plate

Soundalgekar V. M., Uplekar A. G., Jaiswal B. S.

Archives of Mechanics

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2004

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Vol. 56, nr 1

7-17

EN

A finite-difference analysis of transient free convection flow of a dissipative fluid past an infinite vertical porous plate is presented here. Velocity, temperature, skin-friction and Nusselt number are shown graphically and the effects of different parameters on the flow field are discussed.

19

Transient free convection flow of viscous dissipative fluid past a semi-infinite inclined plate

Ganesan P., Palani G.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no 3

395-402

EN

An analysis is performed to study the transient free convection flow of a viscous incompressible fluid past a semi-infinite inclined plate with viscous dissipation. The dimensionless governing equations are unsteady, coupled and non-linear integro partial differential equations. An analytical method fails to give a solution. Hence an implicit finite difference scheme of Crank-Nicolson method is employed. The effect of the dissipation parameter on the velocity, temperature, skin friction and Nusselt number are studied in detail. It is observed that greater viscous dissipative heat causes a rise in the temperature irrespective of the Prandtl number.

20

Magnetohydrodynamic convective flow in a rotating channel

Ghosh S., Bhattacharjee P.

Archives of Mechanics

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2000

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Vol. 52, nr 2

303-318

EN

Combined free and forced convective flow of an electrically conducting viscous incompressible fluid in a rotating parallel plate channel with perfectly conducting walls is investigated. Exact solutions of the governing equations for the fully developed flow are obtained in closed form. It is found that the resultant shear stresses at the walls decrease with the increase in both the rotation parameter K^2 and the magnetic parameter M^2. The rate of heat transfer at both walls decreases with the increase in the Grashof number G.