Dr Raju Chowdhury

Magnetohydrodynamic mixed convection in a double lid driven porous square enclosure filled with copper- water nanofluid with heat generating elliptic block has been numerically simulated in this paper. The governing differential equations are solved by finite element method (Galerkin weighted residual method). The top lid moves at a constant speed with cold temperature. The bottom lid moves at constant speed with heated temperature, linearly heated left and right wall, and a heat generating elliptic body is placed at the center. The magnetic field of strength B is applied parallel to x-axis. Numerical results are obtained for a wide range of parameters such as Darcy number, Grashof number, Reynolds number and copper-water nanofluids is used with Prandtl number of 6.2 throughout the simulation. The streamlines, isotherms, velocity plots and the variation of the average Nusselt number at the hot surface as well as average fluid temperature in the enclosure is presented and discussed. Comparisons with previously numerical works are performed and good agreements between the results are observed. It is found that the governing parameters would result in higher heat transfer. Moreover, it is observed that the both the Darcy number and moving lid ordinations have a significant effect on the flow and thermal fields in the enclosure.

In the present study, natural convective heat and mass transfer and fluid flow inside a window shaped cavity filled with Cu-water nanofluid and containing multiple obstacles with a finite size heater placed in its horizontal wall is numerically investigated. Sinusoidal temperature distribution is maintained by the heater. The left and right inclined walls of the cavity are maintained at a relatively low temperature while the vertical walls are insulated. The governing equations are transformed to the dimensionless form and solved numerically using Galerkin weighted residual technique of finite element method. The influence of pertinent parameters such as thermal Rayleigh number, location of the heater and solid volume fraction of nanoparticles on the heat and mass transfer and fluid flow is studied. The results are obtained in terms of streamlines, isotherms, isoconcentrations, average Sherwood number and average Nueeslt number for the considered parameters and it is observed that the flow pattern, temperature and concentration fields are affected by the variation of the mentioned parameters.

The present work investigates numerically the convective and radiative heat transfer performance and entropy generation of forced convection through a direct absorption solar collector (DASC). Four different fluids; Cu-water nanofluid, Al2O3-waternanofluid, TiO2-water nanofluid and pure water are used as the working fluid. Entropy production has been taken into account in addition to the collector efficiency and heat transfer enhancement. Penalty finite element method with Galerkin's weighted residual technique is used to solve the governing non-linear partial differential equations. Numerical simulations are performed for the variation of solar irradiation (I). The outcomes are presented in the form of isotherms, average output temperature, the average Nusselt number, collector efficiency, average entropy generation and Bejan number. The results present that the rate of heat transfer and collector efficiency enhance significantly for raising the values of I upto a certain range.

In the present study, double-diffusive natural convection flow inside a window shaped cavity containing multiple obstacles filled with nanofluid is studied numerically. Water base nanofluid containing various nanoparticles including Ag, Cu and Al2O3 are considered as working fluid. The left and right inclined walls of the cavity are maintained at a relatively low temperature and low concentration while the vertical walls are adiabatic and impermeable. The non-uniform temperature and concentration are imposed along the bottom wall of the cavity. The governing equations are transformed to the dimensionless form and solved numerically using Galerkin weighted residual technique of finite element method. The influence of pertinent parameters such as thermal Rayleigh number and Lewis number and volume fraction of nanoparticles on the heat and mass transfer and fluid flow is studied. The results are obtained in terms of streamlines, isotherms, isoconcentrations, average Nusselt number and average Sherwood number for the considered parameters and it is observed that the flow pattern, temperature and concentration fields are affected by the variation of the parameters.

The problem of natural convective heat and mass transfer in a triangular enclosure filled with nanofluid saturated porous medium in presence of heat generation has been studied in this paper. The bottom wall of the cavity is heated uniformly, the left inclined wall is heated linearly and the right inclined wall is considered to be cold. The concentration is higher at bottom wall, lower at right inclined wall and linearly concentrated at left inclined wall of the cavity. The governing equations are transformed to the dimensionless form and solved numerically using Galerkin weighted residual technique of finite element method. The results are obtained in terms of streamline, isotherms, isoconcentrations, Nusselt number (Nu) and Sherwood number (Sh) for the parameters thermal Rayleigh number (RaT), Heat generation parameter (¿) and Lewis number (Le) while Prandtl number (Pr), Buoyancy ratio (N) and Darcy number (Da) are considered to be fixed. It is observed that flow pattern, temperature fields and concentration fields are affected by the variation of above considered parameters.

The present paper studies the pulse narrowing nonlinear transmission lines equation, describing pulse narrowing in the field of communication engineering. More precisely, the pulse narrowing nonlinear transmission line equation is solved analytically using the recently developed techniques viz the modified Kudraysov method, the sine-Gordon equation expansion method and the extended sinh-Gordon equation expansion method. As a result, a wide range of dark, bright, dark¿bright, singular or combined singular and optical soliton solutions for the pulse narrowing nonlinear transmission lines equation is formally obtained. All solutions have been verified back into its corresponding equation with the aid of maple package program.

The problem of double-diffusive natural convection of Al2O3-water nanofluid in a porous triangular enclosure in presence of heat generation has been studied numerically in this paper. The bottom wall of the cavity is heated isothermally, the left inclined wall is non-isothermal and the right inclined wall is considered to be cold. The concentration is higher at bottom wall, lower at right inclined wall and non-isoconcentration at left inclined wall of the cavity. The governing equations are transformed to the dimensionless form and solved numerically using Galerkin weighted residual technique of finite element method. The results are obtained in terms of streamlines, isotherms, isoconcentrations, average Nueeslt number (Nu) and average Sherwood number (Sh) for the parameters thermal Rayleigh number (RaT), dimensionless heat generation parameter (¿), solid volume fraction (¿) and Lewis number (Le) while Prandtl number (Pr), Buoyancy ratio (N) and Darcy number (Da) are considered to be fixed. It is observed that flow pattern, temperature fields and concentration fields are affected by the variation of above considered parameters.

The present numerical work is performed to analyze the heat transfer and fluid flow due to free convection in a porous equilateral triangular enclosure with a heated square body in the presence of magnetic field and heat generation. The left inclined wall of the enclosure is adiabatic while the horizontal wall is heated at a uniform temperature; the lower portion of the right inclined wall is considered to be nonisothermal and the upper portion of the wall is cold. The square body is maintained at a constant temperature. The governing equations are solved numerically subject to appropriate boundary conditions by the finite element method using Galerkin's weighted residuals scheme. Results are presented by streamlines, isotherms, mean Nusselt numbers for the different parameters such as Hartmann number (Ha), heat generation (¿), and size of the square body (lb). The Prandtl number (Pr) and Rayleigh number (Ra) are considered fixed. It is observed that the size of the body plays an important role with regard to the heat and fluid flow inside the cavity.