In this study, the effects of radially varying magnetic field, internal heat generation and mixed convection with thermal radiation on peristaltic motion of a non-Newtonian fluid are investigated. The fluid used is third-grade model. The flow is through the gap between two co-axial vertical tubes under the effect of radially varying magnetic field. The outer tube is flexible with sinusoidal deformations. The problem is modulated mathematically by a system of partial differential equations which describes the equations of momentum, heat transfer and nanoparticles concentration which are simplified by using long wave length and low-Reynolds number assumptions. The closed solutions of fluid temperature and nanoparticle concentration are obtained, and the solution of velocity is obtained by using the homotopy perturbation method (HPM). The radially varying magnetic field effect on the axial velocity is discussed and it is shown that the increase of magnetic field parameter tends to reduce the fluid flow.

中文翻译：

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具有蠕动的两个同轴管之间非牛顿纳米流体流动的欧姆耗散和混合对流效应的同伦微扰方法

在这项研究中，研究了径向变化的磁场、内部发热和热辐射混合对流对非牛顿流体蠕动运动的影响。使用的流体为三级模型。在径向变化的磁场作用下，流体通过两个同轴垂直管之间的间隙。外管是柔性的，具有正弦变形。该问题通过偏微分方程系统进行数学调制，偏微分方程系统描述了动量、传热和纳米粒子浓度的方程，这些方程通过使用长波长和低雷诺数假设进行了简化。得到流体温度和纳米粒子浓度的封闭解，利用同伦微扰法(HPM)得到速度的解。