二阶流体通过径向延伸平面时滑移、黏性耗散、焦耳热对MHD流动的影响

Effects of Slip,Viscous Dissipation and Joule Heating on the MHD Flow and Heat Transfer of a Second Grade Fluid Past a Radially Stretching Sheet

研究了二阶导电的非Newton流体,在一个可径向放射状延伸,并伴有部分滑动表面上的流动及其热交换.部分滑移用一个无量纲的滑移因子控制,其取值范围从0(全黏着)到无穷大(全滑移).使用适当的相似变换,把待求的非线性偏微分方程转化为常微分方程.讨论了边界条件的不足,在无需增加任何边界条件下,使用有效的数值格式,求解所得到的微分方程.部分滑移、磁场交互参数以及二阶流体的参数对速度场和温度场的综合分析发现,滑移量的增加,流体的动力边界层和热边界层增厚.因为当滑移量的增加,允许更多的流体通过该平面,表面摩擦因数的数值下降,并在更高的滑移参数下,摩擦因数趋于0,即流体无黏性地通过.还研究了磁场对速度场和温度场的重要影响.

The flow and heat transfer of an electrically conducting non-Newtonian second grade fluid due to an radially stretching surface with partial slip was considered. The partial slip was controlled by a dimensionless slip factor, which varied between zero（ total adhesion） and infinity （full slip）. Suitable similarity transformations were used to reduce the resulting highly nonlinear partial differential equations into ordinary differential equations. The issue of paucity of boundary conditions was addressed and an effective numerical scheme was adopted to solve the obtained differential equations even without augmenting any extra boundary conditions. The important findings in this communication are the combined effects of the partial slip, magnetic interaction parameter and the second grade fluid parameter on the velocity and temperature fields. It is interesting to fred that the slip increases the momentum and thermal boundary layer thickness. As slip increases in magnitude, permitting more fluid to slip past the sheet, the skin friction coefficient decreases in magnitude and approaches zero for higher values of the slip parameter, i.e. the fluid behaves as though it were inviscid. The presence of magnetic field has also substantial effects on velocity and temperature fields.