Eyring-Powell磁纳米流体在伸缩圆柱上的热滑移混合对流（英文）

供热冷却系统的优化设计必须考虑非线性过程的热辐射。本文研究了铜-水纳米流体在伸缩圆筒上的Eyring-Powell磁热辐射的混合对流动力学。考虑非线性热辐射和热滑移条件,建立了能量守衡模型,分析了表面摩擦系数和换热速率等流动参数对流体特性的影响。不采用现有的研究方法,应用最近的谱准线性化方法求解耦合非线性边界值问题。计算结果表明,增大纳米粒子的体积分数、热辐射参数和热源参数可增强温度分布。速度滑移参数和流体材料参数增大了表面摩擦力。对比分析了极限情况下的数值结果和文献结果,结果表明:采用本文研究方法计算结果达到同等精度。

二元谱拟线性化含嗜氧微生物旋转纳米流体的对流边界条件

在本研究中,考虑了旋转的含有嗜氧微生物的黏性、不可压缩的导电纳米流体和漂浮在流体中的绝缘板的三维流动动力学。研究考虑了三种情况:一种是流体拖动板,第二种是板拖动流体,第三种是板以与流体相同的速度漂浮在流体上。浓度较高的嗜氧微生物因流体中氧梯度的作用而上浮到顶部时会产生生物对流。速度比在这种流动的动力学中起关键作用。低于临界值或高于临界值时,改变参数会改变流动的动力学。改变速度比使其低于或高于临界值会改变流体流动的动力学,Hartmann数、浮力比和辐射参数对二次速度有反作用。另一方面,Hall参数对低于或高于临界值的速度比的初始速度有反作用。生物截面的Rayleigh数减慢了初始速度。当速度比低于0.5时,二次速度随着生物截面Rayleigh数的增大而加快。当速度比高于0.5时,对于较小的生物截面Rayleigh数,二次速度起反作用,但随着数值的增加,对流动的作用发生被逆转,起正作用。

On radiative-magnetoconvective heat and mass transfer of a nanofluid past a non-linear stretching surface with Ohmic heating and convective surface boundary condition

In this paper magnetoconvective heat and mass transfer characteristics of a two-dimensional steady flow of a nanofluid over a non-linear stretching sheet in the presence of thermal radiation,Ohmic heating and viscous dissipation have been investigated numerically.The model used for the nanofluid incorporates the effects of the Brownian motion and the presence of nanopanicles in the base fluid.The governing equations are transformed into a system of nonlinear oidinary differential equations by using similarity transformation.The numerical solutions are obtained by using fifth order Runge-Kutta-Fehlberg method with shooting technique.The non-dimensional parameters on velocity,temperature and concentra­tion profiles and also on local Nusselt number and Sherwood number are discussed.The results indicate that the local skin friction coefficient decreases as the value of the magnetic parameter increases whereas the Nusselt number and Sherwood number increase as the values of the Brownian motion parameter and magnetic parameter increase.

Modeling control of foot and mouth disease with two time delays

We develop a delay ordinary differential equation model that captures the effects of prophylactic vaccination, reactive vaccination, prophylactic treatment and reactive culling on the spread of foot and mouth disease (FMD) with time delays. Simulation results from the study suggest that increasing time delay while increasing the control strategies decreases the burden of FMD. Further, the results reveal, that decreasing time delay while decreasing the control strategies increases the burden of FMD. The intermediate scenarios of either (i) increasing time delay while decreasing control or (ii) decreasing time delay while increasing control have intermediate effects on burden reduction. Thus, the implementation of effective control strategies combination can play an important role in mitigating against the FMD burden.