Uddin Mohammed J, Khan Waqar A, Amin Norsarahaida S
Department of Mathematics, American International University- Bangladesh, Banani, Dhaka, Bangladesh.
Department of Engineering Sciences, PN Engineering College, National University of Sciences and Technology, Karachi, Pakistan.
PLoS One. 2014 Jun 13;9(6):e99384. doi: 10.1371/journal.pone.0099384. eCollection 2014.
The unsteady two-dimensional laminar g-Jitter mixed convective boundary layer flow of Cu-water and Al2O3-water nanofluids past a permeable stretching sheet in a Darcian porous is studied by using an implicit finite difference numerical method with quasi-linearization technique. It is assumed that the plate is subjected to velocity and thermal slip boundary conditions. We have considered temperature dependent viscosity. The governing boundary layer equations are converted into non-similar equations using suitable transformations, before being solved numerically. The transport equations have been shown to be controlled by a number of parameters including viscosity parameter, Darcy number, nanoparticle volume fraction, Prandtl number, velocity slip, thermal slip, suction/injection and mixed convection parameters. The dimensionless velocity and temperature profiles as well as friction factor and heat transfer rates are presented graphically and discussed. It is found that the velocity reduces with velocity slip parameter for both nanofluids for fluid with both constant and variable properties. It is further found that the skin friction decreases with both Darcy number and momentum slip parameter while it increases with viscosity variation parameter. The surface temperature increases as the dimensionless time increases for both nanofluids. Nusselt numbers increase with mixed convection parameter and Darcy numbers and decreases with the momentum slip. Excellent agreement is found between the numerical results of the present paper with published results.
采用隐式有限差分数值方法结合拟线性化技术，研究了Cu - 水和Al₂O₃ - 水纳米流体在达西多孔介质中绕渗透拉伸平板的非稳态二维层流g - 抖动混合对流边界层流动。假设平板受到速度和热滑移边界条件的作用。考虑了粘度随温度变化的情况。在进行数值求解之前，通过适当的变换将控制边界层方程转化为非相似方程。结果表明，输运方程受多个参数控制，包括粘度参数、达西数、纳米颗粒体积分数、普朗特数、速度滑移、热滑移、抽吸/注入以及混合对流参数。以图形方式给出并讨论了无量纲速度和温度分布以及摩擦系数和传热速率。研究发现，对于具有恒定和可变性质的流体，两种纳米流体的速度均随速度滑移参数而降低。进一步发现，表面摩擦随达西数和动量滑移参数减小，而随粘度变化参数增大。两种纳米流体的表面温度均随无量纲时间增加而升高。努塞尔数随混合对流参数和达西数增加，随动量滑移减小。本文的数值结果与已发表结果之间具有良好的一致性。
