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Theoretical research has been done on the hydromagnetic three-dimensional nanofluid flow across an inclined stretching sheet in the presence of Brownian motion and thermophoresis. It is taken into account that there are two different kinds of water-based nanofluids that contain copper and alumina. Three-dimensional nonlinear-type similarity transformations are used to convert the governing boundary-layer equations into a collection of similarity equations, which are then numerically solved by MATLAB. Further, results obtained in some limiting cases are compared to some results that have already been published, and it is found that there is good agreement. The problem is controlled by a number of physical factors, and the impact of these factors on different flow distributions is thoroughly examined with the help of graphs and tables. It has been observed that the nanofluid has better heat transfer conductivity than the ordinary base fluid. [ABSTRACT FROM AUTHOR]

In this study, numerical experimentation was performed to explore the impact of electro-thermo-convection on unsteady combined convection flow within a square chamber driven by dual ventilation channels with opposing flow. An electrical emitter was placed on the left wall to influence the hot wall, with a collector electrode on the other wall, while the remaining walls were thermally and electrically insulated. The equations which govern the system were solved using the finite difference method with an alternate direction implicit scheme and an iterative successive under-relaxation (SUR) technique. Key physical parameters, including Reynolds number (50 ≤ R e ≤ 500), Richardson number (0.1 ≤ R i ≤ 20), and a range of electrical Rayleigh numbers (0 ≤ R a e ≤ 1200), were examined for their effects on charge density distribution, streamlines, isotherms, and the mean Nusselt number. The study reveals that electrical effects significantly boost heat transfer, with an 88% increase in the mean Nusselt number under low forced convection and buoyancy (R i = 0.1 , R e = 50). However, as buoyancy (R i = 20) and forced ventilation (R e = 500) intensify, this enhancement decreases to 25% and 33%, indicating that these forces moderate the influence of electrical effects. Additionally, Richardson and Reynolds numbers strongly affect heat transfer, with rates increasing by 52% and 126%, respectively, under pure thermal convection. The numerical model results align well with previous research, suggesting the potential application of advanced cooling techniques to enhance the heat transfer efficiency in an electronic devices and similar systems. [ABSTRACT FROM AUTHOR]

The present study is proposed to investigate the effects of various lengths and different locations of the heater on the left sidewall in a square lid-driven porous cavity filled with nanofluid. A higher temperature is maintained on the left wall where three different lengths and three different locations of the heat source are considered for the analysis. The right wall is kept at a lower temperature while the top and bottom walls, and the remaining portions of the heated wall are adiabatic. The governing equations are solved by finite volume method. The results show that among the different lengths of the heat source, an enhancement in the heat transfer rate is observed only for the length LH = 1/3 of the heat source. In the case of location of the heat source, the overall heat transfer rate is increased when the heat source is located at the top of the hot wall. For Ri = 1 and 0.01, a better heat transfer rate is obtained when the heat source is placed at the top of the hot wall whereas for Ri = 100, it occurs when the heating portion is at the middle of the hot wall. As the solid volume fraction increases, the viscosity of the fluid is increased, which causes a reduction in the flow intensity. An addition of nanoparticles in the base fluid enhances the overall heat transfer rate significantly for all Da considered. The permeability of the porous medium plays a major role in convection of nanofluid than porosity. A high heat transfer rate (57.26%) is attained for Da = 10−1 and χ = 0.06.

This research explores the heat transfer rate for micropolar fluid in a channel flow. In spite of formal Fourier's law, the Cattaneo–Christov heat flux design is implemented in energy system. Using appropriate dimensionless parameters, the guiding coupled partial differential equations that represent the fluid flow are modified into ordinary differential equations. By executing Runge–Kutta integration procedure and the shooting method, the numerical results are achieved. The impacts of thermal relaxation time and bio-convection flow of micropolar fluid are examined in this assessment. Graphical analyses are used to assess the effects of physical factors for the momentum, micro-rotation, concentration, density of micro-organisms and temperature gradient. The skin friction values, motile density number, heat and mass transfer rate are the fascinating physical quantities whose numerical data are computed and validated against different parametric values. The variational iteration method (VIM) and Adomian decomposition method are the analytical modules which have been incorporated here for solving the nonlinear systems for showing better approximity. It is found from the study that larger the thermal relaxation time values, the more likely they are to increase heat transfer, hence lowering the fluid temperature. Moreover, both Fourier and Cattaneo–Christov heat conduction module exhibit qualitatively similar influence on embedded parameters also the temperature profile diminishes for larger values of Pe h . The culminations evidently disclose that the bio-convection Peclet number and the motile microbes parameter enhance the density of motile micro-organisms. From a computational perspective, the VIM is more effective, practical and ease of use. The numerical and analytical results are compared well with the existing articles. The optimum parameter level for maximum heat transfer is considered to be A 3 B 4 C 1 D 2 E 3. Taguchi approach was successfully used to determine the optimum design parameters for maximum heat transfer is 1.724012 for the parameters A-5:B-5:C-0.5:D-0.5:E-0.7. [ABSTRACT FROM AUTHOR]

This study explores the complex interactions between rotation, chemical reactions, and electroconvection in Maxwell dielectric nanofluids within anisotropic porous media. The research aims to elucidate how these factors influence the heat transfer efficiency and fluid dynamics under the influence of external alternating current (AC) electric fields. The normal mode method is employed to analyse the stability of the system, allowing for the examination of oscillatory modes and their growth rates. By introducing perturbations in the physical parameters, the study derives a set of ordinary linear differential equations that characterize the system's response to external influences. The coupled differential equations were solved using the Galerkin approach for first approximation while meeting the necessary boundary conditions. Analytical solution of the representative equation for stress-free boundary states yields Rayleigh number formulas for nonoscillatory and oscillatory mode occur. Oscillatory modes are seen for both bottom and top-heavy nanoparticle distributions. The electric Rayleigh number, thermal Prandtl number, and stress relaxation parameter increases, whereas the Brinkman-Darcy number delays the onset of stationary and oscillatory convection. The study finds that positive concentration Rayleigh numbers stabilize the system, while negative ones lead to instability. Additionally, it demonstrates that external alternating current electric fields influence convection behavior and provides formulas for critical Rayleigh numbers, enhancing our understanding of fluid interactions in various engineering and technological applications. [ABSTRACT FROM AUTHOR]

Gold nanoparticles with specialised properties have been utilised for aesthetic purposes throughout history. These nanoparticles are characterised by their size, aspect ratio, and optical features, available in both spherical and non-spherical forms. Various industries, including food, pharmaceuticals, and water purification, make use of gold nanoparticles. Due to their diverse applications, these nanoparticles are employed in addressing stenosis by managing blood flow. The analytical study focuses on blood flow through a typical catheterised artery with stenosis, considering the influence of microorganisms and gold (AU) nanoparticles. Cylindrical coordinates are employed for the examination of blood vessels, and governing equations with appropriate boundary conditions are developed for the cylindrical artery under the assumption of minor stenosis. The Cauchy-Euler technique is applied to obtain precise solutions to the analytical equations. The results indicate that AU nanoparticles enhance blood flow in arteries through heat emission, regulating the axial velocity of the flow. Graphs representing physical parameters such as velocity, temperature, resistance impedance, shear stress, nanoparticle concentration, and microorganism concentration are plotted. The impact of concentration, velocity, temperature, and other factors is illustrated through various stenoses characterised by the form parameter, stenosis height, and catheter radius. Additionally, the Peclet number and Grashof number are analysed for different physical factors. [ABSTRACT FROM AUTHOR]

In this study, the Homotopy Analysis Method (HAM) is employed to investigate the flow of a Ferro-hydrodynamic bio-nanofluid over a co-axial rotating disks with Stefan blowing, magnetic dipole, and hall effects. The heat transport mechanism is modeled by using the Brownian movement and thermophoresis. The governing equations are derived and transformed into nondimensional form using appropriate similarity transformations. The resulting equations are solved analytically using the Homotopy Analysis Method. The obtained results are compared with the existing literature and are found to be in excellent agreement. The effects of various parameters such as Hartmann number (Ha), Ferro-hydrodynamic interaction parameter (B), Stefan blowing effect (f w) , Peclet (Pe), and bio-convection Lewis number (Lb) are examined via graphical representation. Moreover, the bio-nanofluid radial velocity field is enhanced by improving the values of hall and Ferro-hydrodynamic interaction parameter (FHD). The temperature profile is diminished due to increasing the values of hall parameter, while the opposite behavior is observed when rising the values of FHD parameter. Increasing the Hartmann number (Ha) lead to decline the radial and tangential velocity, whereas the temperature profile is enhanced. The motile microorganisms filed is significantly affected by bio-Lewis and Peclet numbers. The significance of Stefan blowing is discussed on the hydrodynamic, heat, and mass transport aspects for the instances of f w < 0 , fw = 0, and f w > 0 , respectively. Also, the drag coefficient, heat and mass transport, motile microorganisms rates are discussed via tables. [ABSTRACT FROM AUTHOR]