Papers by Keyword: Slip Flow

Abstract: This study considers the unsteady magnetohydrodynamic slip flow past a permeable stretching cylinder by taking into account the Soret and Dufour effects. Using similarity transformations, the partial differential equations governing the flow, heat, and mass transfers are transformed into a system of ordinary differential equations. These equations are numerically solved for a variety of governing parameter values using the boundary value problem solved package, bvp4c, which is available in the MATLAB software. The outcomes of the governing parameters on the skin friction coefficient, Nusselt and Sherwood numbers are also examined. Upon observation, the unsteadiness parameter influences a positive growth on the momentum, thermal and concentration boundary layers. Slip parameter can be enhanced to improve the friction drag force about 28% and the rate of cooling around 3%. Also, larger effects of Dufour leads to around 9% decay in heat transfer rate and Soret effect to cause around 11% drop in mass transfer rate. Comparison with existing results show excellent agreement which justifies the reliability of the obtained results.

Abstract: The impact of space dependent heat source in the transport of micropolar fluid in the existence of magnetic dipole, Joule heating, viscous heating, thermal radiation, hydrodynamic slips and convective condition effects has been numerically investigated. The dimensioned governing equations are non-dimensionlzed by using dimensionless variables then non-dimensional forms of the corresponding equations are than tackled by the versatile Finite Element Method (FEM). The effects of pertinent physical parameters characterize the flow phenomena are presented through graphs and discussed. It is found that, the impact of thermal based heat source advances the heat transfer characteristics significantly than exponential to space dependent. The thermal performance can be improved through the effects of magnetic dipole, viscous heating, Joule heating and convective condition. Further, the present numerical results are compared with previously published results in the literature as a limiting case of the considered problem and found to be in good agreement with the existing results.

Abstract: This article deals with the analytical study of MHD flow and heat transfer over a permeable stretching sheet via homotopy analysis method (HAM). The effect of thermal radiation is included in the energy equation, while velocity and thermal slips are included in the boundary conditions. The governing boundary layer equations are transformed into a set of ordinary differential equations by means of similarity transformations. The effects of different parameters on the flow field and heat transfer characteristics are examined. The results obtained were shown to compare well with the numerical results and for some special cases with the published data available in the literature, which are in favorable agreement. Keywords: MHD; Slip flow; Stretching sheet; Thermal radiation; Homotopy analysis method

Abstract: A theoretical and numerical examination has been completed to talk about the unsteady, two dimensional slip flow of a nanofluid of heat and mass transfer with transverse magnetic field was investigated in this paper. A stretching surface is used to investigate the flow. Obtained nonlinear equations are solved by Spectral Relaxation Method (SRM) technique and the results are verified by comparing the results obtained by using the Matlab in-built boundary value problem solver bvp4c, and the outcomes which are published in previous papers. The outcomes are exhibited pictorially and talked about difference coming about parameters. Expanding heat transfer rate, mass transfer rate and velocity slip raises velocity yet to be diminishes temperature and skin friction (surface shear stress).

Abstract: A theoretical investigation of a hydromagnetic boundary layer flow of Carreau fluid over a stretching cylinder with surface slippage and temperature jump is presented in this paper. It is assumed that heat transfer characteristics of the flow follows Cattaneo-Christov heat flux model base on conventional Fourier’s law with thermal relaxation time. The spectral relaxation method (SRM) is being utilized to provide the solution of highly nonlinear system of coupled partial differential equations converted into dimensionless governing equations. The behaviour of flow parameters on velocity, temperature distributions are sketched as well as analyzed physically. The result indicates that the temperature distribution decay for higher temperature jump and thermal relaxation parameters respectively.

Abstract: A mathematical model is proposed to the magnetohydrodynamic (MHD) slip flow in a shrinking permeable channel to simulate and scrutinize the effects of Hall current in a rotating frame of reference. The lower plate of the channel is shrinking permeable and subjected to uniform suction. The partial differential equations governing the flow are transformed into a system of ordinary differential equations using suitable similarity transformation. Numerical computations are performed with the shooting iteration scheme alongside Runge-Kutta fourth-order method. The physical behavior of obtained solution are investigated diagrammatically by considering the effects of various pertinent parameters. Numerical results reveal that an increase in Hall parameter leads to an increase in secondary flow. Results also reveal that rotation and slip at the surface of sheet substantially influence the flow, and control the shear stress.

Abstract: The influence of thermal radiation on a two-dimensional non-Newtonian fluid flow past a slendering stretching surface is investigated theoretically. Casson and Williamson fluid models are considered with Soret and Dufour effects. The transformed ODEs are solved numerically using the bvp5c Matlab package and dual solutions are executed for Casson and Williamson fluid cases. The influence of various parameters, namely, thermal radiation parameter, cross diffusion parameters and slip parameters on velocity, thermal and concentration distributions are discussed with the assistance of graphs. The local Nusselt and Sherwood numbers are computed and presented through tables. It is observed that the influence of cross diffusion is higher on Williamson flow when equated with the Casson flow.

Abstract: The current paper covers the examination of 3D nanofluid motion over a slendering expanding sheet under the influence of slip effect and thermal radiation. In this study, we considered the Cu-water and Al₅₀Cu₅₀-water nanofluids over a non-uniform thickness expanding sheet. With the help of similitude transformations, we changed the derived governed equations as ordinary differential equations. The mathematical outcomes determined by using Runge-Kutta and Newton’s methods. We reveal and interpret the graphs for different parameters of interest. We discussed the skin friction coefficient and reduced Nusselt number at different pertinent parameters. Results shown that the rate of heat transfer is higher in Al₅₀Cu₅₀-water nanofluid when compared with Cu-water nanofluid.

Abstract: Three-dimensional magnetohydromagnetic slip flow of chemically reacting fluid over a variable thickness stretching sheet with space and temperature dependent heat source/sink was analysed numerically. Runge-Kutta and Newton’s methods are employed for solving the reduced ordinary differential equations with the help of similarity variables. Plots are demonstrated and examined for several parameters of concern. Also the effect of the same parameters on skin friction coefficient, heat and mass transfer rates are presented in tabular form. We found a good agreement of the present results by comparing with the published results. It is observed that space and temperature dependent heat source/sink parameters acts like controlling parameters of heat transfer. Slip effects reduce the development of concentration and thermal boundary layers.

Abstract: Ultrathin gas film lubrication has been widely used in recent years, such as dry gas seal face gas lubrication, gas lubrication in the hard disk drive, etc. The rarefied gas effect must be considered when the gas film thickness is very thin. In order to analyze, compare, and select the appropriate rarefied effect model on gas lubrication, a comparative analysis has been carried out on the influence laws of the Poiseuille flow rate and the ratio of the effective viscosity coefficients and the dynamic viscosity, μ_eff/μ, with inverse Knudsen number, D ,or Knudsen number, K_n, as to different models. The results show that when inverse Knudsen number increases or Knudsen number decreases, the Poiseuille flow rate and the ratio of the effective viscosity coefficients and the dynamic viscosity,μ_eff/μ, of different models approach to each other. However, there are significant differences as to different models when the Knudsen number is large, and only several models from Hwang, Veijola, Peng etc agree with Fukui’s model.