AbstractPresent research article reports the magnetized impacts of Cattaneo-Christov double diffusion models on heat and mass transfer behaviour of viscous incompressible, time-dependent, two-dimensional Casson nanofluid flow through the channel with Joule heating and viscous dissipation effects numerically. The classical transport models such as Fourier and Fick’s laws of heat and mass diffusions are generalized in terms of Cattaneo-Christov double diffusion models by accounting the thermal and concentration relaxation times. The present physical problem is examined in the presence of Lorentz forces to investigate the effects of magnetic field on double diffusion process along with Joule heating. The non-Newtonian Casson nanofluid flow between two parallel plates gives the system of time-dependent, highly nonlinear, coupled partial differential equations and is solved by utilizing RK-SM and bvp4c schemes. Present results show that, the temperature and concentration distributions are fewer in case of Cattaneo-Christov heat and mass flux models when compared to the Fourier’s and Fick’s laws of heat and mass diffusions. The concentration field is a diminishing function of thermophoresis parameter and it is an increasing function of Brownian motion parameter. Finally, an excellent comparison between the present solutions and previously published results show the accuracy of the results and methods used to achieve the objective of the present work.

S u p e r c ri tic al h e a t t r a n sf e r c h a r a c t e ri s tic s of c o u pl e s t r e s s c o nv e c tio n flo w fro m a v e r ti c al cyli n d e r u si n g a n e q u a tio n of s t a t e a p p r o a c h B a s h a , H , R e d dy, GJ, N a r a y a n a n , N SV a n d B e g, OA h t t p:// dx. doi.o r g/ 1 0. 1 0 1 6/j. m olliq. 2 0 1 8. 1 1. 1 6 5Ti t l e S u p e r c ri tic al h e a t t r a n sf e r c h a r a c t e ri s tic s of c o u pl e s t r e s s c o nv e c tio n flow fro m a v e r ti c al cylin d e r u si n g a n e q u a tio n of s t a t e a p p r o a c h A u t h o r s B a s h a , H , R e d dy, GJ, N a r a y a n a n, N SV a n d B e g, OA Typ eArticl e U RL This ve r sio n is a v ail a bl e a t : h t ABSTRACTThe present work describes numerical simulations of the supercritical heat transfer characteristics of couple stress fluid flow from a vertical cylinder using the equation of state approach. Redlich-Kwong (RK-EOS) and Van der Waals (VW-EOS) equations of state (EOS) are deployed to derive the equation for the thermal expansion coefficient ( ). The values calculated based on RK-EOS are sufficiently close to the experimental values when compared with those based on VW-EOS. Due to the presence of couple stresses in the fluid, highly nonlinear coupled partial differential equations are generated. These primitive equations are reduced to dimensionless form by using suitable non-dimensional quantities. An unconditionally stable finite difference technique is used to solve the normalized conservation equations under physically viable boundary conditions, in order to describe the natural convection heat transfer characteristics of couple stress fluid external to a vertical cylinder in the supercritical region. For different values of the emerging physical parameters, numerical data for couple stress fluid for the case of Nitrogen is generated and presented in the form of graphs and tables. The present computations indicate that the velocity field is suppressed close to the cylinder whereas it is enhanced away from the cylinder with increasing values of reduced temperature in the supercritical fluid region. The reverse behavior is observed for reduced pressure. The present results are compared with the previous results and found to be in good agreement. Applications of the model include super-critical coating dynamics in the aerospace and medical industries.

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The present numerical study reports the chemically reacting boundary layer flow of a magnetohydrodynamic second-grade fluid past a stretching sheet under the influence of internal heat generation or absorption with work done due to deformation in the presence of a porous medium. To distinguish the non-Newtonian behaviour of the second-grade fluid with those of Newtonian fluids, a very popularly known second-grade fluid flow model is used. The fourth order momentum equation with four appropriate boundary conditions along with temperature and concentration equations governing the second-grade fluid flow are coupled and highly nonlinear in nature.Well-established similarity transformations are efficiently used to reduce the dimensional flow equations into a set of nondimensional ordinary differential equations with the necessary conditions. The standard bvp4c MATLAB solver is effectively used to solve the fluid flow equations to get the numerical solutions in terms of velocity, temperature, and concentration fields. Numerical results are obtained for a different set of physical parameters and their behaviour is described through graphs and tables.The viscoelastic parameter enhances the velocity field whereas the magnetic and porous parameters suppress the velocity field in the flow region. The temperature field is magnified for increasing values of the heat source/sink parameter. However, from the present numerical study, it Heat Transfer-Asian Res. 2019;48:1595-1621.wileyonlinelibrary.com/journal/htj

In this research article, the electrically conducting magnetized radiative squeezed flow of two-dimensional time-dependent viscous incompressible flow between two parallel disks with heat source/sink and Joule heating effects under the presence of an unsteady homogeneous first order chemical reaction is demonstrated numerically. The considered physical problem is studied under the influence of Lorentz forces to describe the effect of an applied magnetic field. Heat dissipation due to viscosity and Joule heating are considered in the energy equation to demonstrate the behavior of the thermal profile. Also, the thermodynamic behavior of temperature field is described by considering the concept of heat source/sink in the energy equation. The mass transport characteristics of a viscous fluid are described through the time-dependent chemical reaction of first order type with homogenous behavior. Thus, the considered physical problem gives the time-dependent, highly nonlinear coupled partial differential equations, which are reduced to a system of ordinary differential equations by invoking the suitable similarity transformations. The discretized first order ordinary differential equations are solved by using the Runge-Kutta fourth order integration scheme with the