scholarly journals Study of ramped temperature influence on MHD convective chemically reactive and absorbing fluid past an exponentially accelerated vertical porous plate

2018 ◽  
Vol 15 (2) ◽  
pp. 107-125
Author(s):  
M C Raju ◽  
S Harinath Reddy ◽  
Dr. E. Keshava Reddy

A systematic study has been performed on MHD convective chemically reactive and absorbing fluid along an exponentially accelerated vertical plate with the impact of Hall current by considering ramped temperature. Laplace transform technique is applied to obtain exact solutions of the non-dimensional governing equations for fluid velocity, temperature and concentration. Based on these solutions, the expressions for skin friction coefficient, Nusselt number and Sherwood number are also derived. The consequences of diverse physical parameters on flow quantities are examined thoroughly with graphical representations. The numerical values for skin friction coefficient, rate of heat transfer and rate of mass transfer are recorded and analyzed.

NANO ◽  
2013 ◽  
Vol 08 (01) ◽  
pp. 1350001 ◽  
Author(s):  
P. LOGANATHAN ◽  
P. NIRMAL CHAND ◽  
P. GANESAN

An exact analysis is carried out to study the radiation effects on an unsteady natural convective flow of a nanofluid past an impulsively started infinite vertical plate. The nanofluids containing nanoparticles of aluminium oxide, copper, titanium oxide and silver with nanoparticle volume fraction range less than or equal to 0.04 are considered. The partial differential equations governing the flow are solved by Laplace transform technique. The influence of various parameters on velocity and temperature profiles, as well as Nusselt number and skin-friction coefficient, are examined and presented graphically. An increase in radiation parameter and time leads to fall in temperature of the fluid. The presence of nanoparticles and thermal radiation increases the rate of heat transfer and skin friction. The effect of heat transfer is found to be more pronounced in silver water nanofluid than in the other nanofluids. It is observed that the fluid velocity increases with an increase in Grashof number and time. Excellent validation of the present results is achieved with existing results in the literature.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
M. Irfan ◽  
M. Asif Farooq ◽  
A. Mushtaq ◽  
Z. H. Shamsi

This research aims at providing the theoretical effects of the unsteady MHD stagnation point flow of heat and mass transfer across a stretching and shrinking surface in a porous medium including internal heat generation/absorption, thermal radiation, and chemical reaction. The fundamental principles of the similarity transformations are applied to the governing partial differential equations (PDEs) that lead to ordinary differential equations (ODEs). The transformed ODEs are numerically solved by the shooting algorithm implemented in MATLAB, and verification is done from MATLAB built-in solver bvp4c. The numerical data produced for the skin friction coefficient, the local Nusselt number, and the local Sherwood number are compared with the available result and found to be in a close agreement. The impact of involved physical parameters on velocity, temperature, concentration, and density of motile microorganisms profiles is scrutinized through graphs. It is analyzed that the skin friction coefficient enhances with increasing values of an unsteady parameter A , magnetic parameter M , and porosity parameter Kp . In addition, we observe that the density of a motile microorganisms profile enhances larger values of the bioconvection Lewis number Lb and Peclet number Pe and decreases with the increasing values of an unsteady parameter A .


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
O. D. Makinde ◽  
M. S. Tshehla

This paper investigates the unsteady hydromagnetic-free convection of an incompressible electrical conducting Boussinesq’s radiating fluid past a moving vertical plate in an optically thin environment with the Navier slip, viscous dissipation, and Ohmic and Newtonian heating. The nonlinear partial differential equations governing the transient problem are obtained and tackled numerically using a semidiscretization finite difference method coupled with Runge-Kutta Fehlberg integration technique. Numerical data for the local skin friction coefficient and the Nusselt number have been tabulated for various values of parametric conditions. Graphical results for the fluid velocity, temperature, skin friction, and the Nusselt number are presented and discussed. The results indicate that the skin friction coefficient decreases while the heat transfer rate at the plate surface increases as the slip parameter and Newtonian heating increase.


2019 ◽  
Vol 392 ◽  
pp. 1-9 ◽  
Author(s):  
Ram Prakash Sharma ◽  
M.C. Raju ◽  
Oluwole Daniel Makinde ◽  
P.R. Krishna Reddy ◽  
P. Chandra Reddy

An unsteady magnetohydrodynamic natural convection transfer of mass and heat flow over a vertical porous sheet under the influence of thermal radiation and thermo-diffusion effect. The dimensionless governing equations are solved analytically by employing Laplace transform technique. The impact of various physical parameters on momentum, energy and concentration are discussed and analyzed with the aid of graphs. Furthermore, the numerical values for local Skin friction, Nusselt number and Sherwood number are noted and examined. Increasing the values of thermal diffusion results in increasing of the concentration, but it decreases with Schmidt number. Skin friction reduces for increasing values of thermo-diffusion are discussed with the help of tables.


Author(s):  
Rajesh Vemula ◽  
A J Chamkha ◽  
Mallesh M. P.

Purpose – The purpose of this paper is to focus on the numerical modelling of transient natural convection flow of an incompressible viscous nanofluid past an impulsively started semi-infinite vertical plate with variable surface temperature. Design/methodology/approach – The problem is governed by the coupled non-linear partial differential equations with appropriate boundary conditions. A robust, well-tested, Crank-Nicolson type of implicit finite-difference method, which is unconditionally stable and convergent, is used to solve the governing non-linear set of partial differential equations. Findings – The local and average values of the skin-friction coefficient (viscous drag) and the average Nusselt number (the rate of heat transfer) decreased, while the local Nusselt number increased for all nanofluids, namely, aluminium oxide-water, copper-water, titanium oxide-water and silver-water with an increase in the temperature exponent m. Selecting aluminium oxide as the dispersing nanoparticles leads to the maximum average Nusselt number (the rate of heat transfer), while choosing silver as the dispersing nanoparticles leads to the minimum local Nusselt number compared to the other nanofluids for all values of the temperature exponent m. Also, choosing silver as the dispersing nanoparticles leads to the minimum skin-friction coefficient (viscous drag), while selecting aluminium oxide as the dispersing nanoparticles leads to the maximum skin-friction coefficient (viscous drag) for all values of the temperature exponent m. Research limitations/implications – The Brinkman model for dynamic viscosity and Maxwell-Garnett model for thermal conductivity are employed. The governing boundary layer equations are written according to The Tiwari-Das nanofluid model. A range of nanofluids containing nanoparticles of aluminium oxide, copper, titanium oxide and silver with nanoparticle volume fraction range less than or equal to 0.04 are considered. Practical implications – The present simulations are relevant to nanomaterials thermal flow processing in the chemical engineering and metallurgy industries. This study also provides an important benchmark for further simulations of nanofluid dynamic transport phenomena of relevance to materials processing, with alternative computational algorithms (e.g. finite element methods). Originality/value – This paper is relatively original and illustrates the influence of variable surface temperature on transient natural convection flow of a viscous incompressible nanofluid and heat transfer from an impulsively started semi-infinite vertical plate.


2022 ◽  
Vol 52 (1) ◽  
pp. 35-41
Author(s):  
Silpisikha Goswami ◽  
Kamalesh Kumar Pandit ◽  
Dipak Sarma

Our motive is to examine the impact of thermal radiation and suction or injection with viscous dissipation on an MHD boundary layer flow past a vertical porous stretched sheet immersed in a porous medium. The set of the flow equations is converted into a set of non-linear ordinary differential equations by using similarity transformation. We use Runge Kutta method and shooting technique in MATLAB Package to solve the set of equations. The impact of non-dimensional physical parameters on flow profiles is analysed and depicted in graphs. We observe the influence of non-dimensional physical quantities on the Nusselt number, the Sherwood number, and skin friction and presented in tables. A comparison of the obtained numerical results with existing results in a limiting sense is also presented. We enhance radiation to observe the deceleration of fluid velocity and temperature profile for both suction and injection. While enhancing porosity parameter accelerates velocity whereas decelerates temperature profile. As the heat source parameter increases, the temperature of the fluid decreases for both suction and injection, it has been found. With the increasing values of the radiation parameter, the skin friction and heat transfer rate decreases. Increasing magnetic parameter decelerates the skin friction, Nusselt number, and Sherwood number.


2013 ◽  
Vol 62 (3) ◽  
Author(s):  
Muhamad Najib Zakaria ◽  
Abid Hussanan ◽  
Ilyas Khan ◽  
Sharidan Shafie

The present paper is on study of the influence of radiation on unsteady free convection flow of Brinkman type fluid near a vertical plate containing a ramped temperature profile. Using the appropriate variables, the basic governing equations are reduced to nondimensional equations valid with the imposed initial and boundary conditions. The exact solutions are obtained by using Laplace transform technique. The influence of radiation near a ramped temperature plate is also compared with the flow near a plate with constant temperature. The numerical computations are carried out for various values of the physical parameters such as velocity, temperature, skin friction and Nusselt number and presented graphically.


2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Zahir Shah ◽  
Saeed Islam ◽  
Hamza Ayaz ◽  
Saima Khan

The present research aims to examine the micropolar nanofluid flow of Casson fluid between two parallel plates in a rotating system with effects of thermal radiation. The influence of Hall current on the micropolar nanofluids have been taken into account. The fundamental leading equations are transformed to a system of nonlinear differential equations using appropriate similarity variables. An optimal and numerical tactic is used to get the solution of the problem. The convergence and comparison have been shown numerically. The impact of the Hall current, Brownian movement, and thermophoresis phenomena of Casson nanofluid have been mostly concentrated in this investigation. It is found that amassed Hall impact decreases the operative conductivity which intends to increase the velocity field. The temperature field enhances with larger values of Brownian motion thermophoresis effect. The impacts of the Skin friction coefficient, heat flux, and mass flux have been deliberate. The skin friction coefficient is observed to be larger for k=0, as compared to the case of k=0.5. Furthermore, for conception and visual demonstration, the embedded parameters have been deliberated graphically.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Ashish Paul

This paper is concerned with analytical solution of one-dimensional unsteady laminar boundary layer MHD flow of a viscous incompressible fluid past an exponentially accelerated infinite vertical plate in presence of transverse magnetic field. The vertical plate and the medium of flow are considered to be porous. The fluid is assumed to be optically thin and the magnetic Reynolds number is considered small enough to neglect the induced hydromagnetic effects. The governing boundary layer equations are first converted to dimensionless form and then solved by Laplace transform technique. Numerical values of transient velocity, temperature, skin friction, and Nusselt number are illustrated and are presented in graphs for various sets of physical parametric values, namely, Grashof number, accelerating parameter, suction parameter, permeability parameter, radiation parameter, magnetic parameter, and time. It is found that the velocity decreases with increases of the suction parameter for both cases of cooling and heating of the porous plate whereas skin friction increases with increase of suction parameter.


2008 ◽  
Vol 35 (4) ◽  
pp. 323-331 ◽  
Author(s):  
R. Muthucumaraswamy ◽  
K.E. Sathappan ◽  
R. Natarajan

An exact solution to the problem of flow past an exponentially accelerated infinite vertical plate with variable temperature is analyzed. The temperature of the plate is raised linearly with time t. The dimensionless governing equations are solved using Laplace-transform technique. The velocity and temperature profiles are studied for different physical parameters like thermal Grashof number Gr, time and an accelerating parameter a. It is observed that the velocity increases with increasing values of a or Gr.


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