Effect of Hall Current on the MHD Natural Convection Flow From a Vertical Permeable Flat Plate With Uniform Surface Heat Flux
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摘要: 在横向磁场作用下,研究Hall电流对竖直可渗透平板上MHD自然对流的影响,平板具有均匀的热通量.和外部磁场相比,假设感应磁场可以忽略不计.利用自由变量公式化(FVF)和流函数公式化(SFF),将边界层方程简化为适当的形式.对局部蒸发系数ζ的整个取值范围,由FVF得到的抛物型方程,用简明的有限差分法进行数值积分;另一方面,由SFF得到的非相似方程,采用局部非相似法求解.有些区域,如局部蒸发系数ζ值足够大或足够小时,用正规的摄动法求解.对低值Prandtl数Pr,例如Pr=0.005,0.01,0.05时,用图形表示磁场参数M和Hall参数m,对局部表面摩擦因数和局部Nusselt数的影响.最后对不同的局部蒸发系数ζ值,给出流体的速度和温度分布.Abstract: The effect of Hall current on the MHD natural convection flow from a vertical permeable flat plate with uniform heat flux in the presence of transverse magnetic field was analyzed.It was assumed that the induced magnetic field was negligible compared to the imposed magnetic field.The boundary layer equations were reduced to the suitable form by employing free variable formulation (FVF) and stream function formulation (SFF).The parabolic equations obtained from FVF were integrated numerically with the help of straightforward finite difference method while on the other hand nonsimilar system of equations obtained from SFF were solved by employing local non-similarity method,for the whole range of local transpiration parameter ζ.Consideration had also been given to the regions where local transpiration parameter ζ was small or large enough.However,in these particular regions,solutions were acquired with the aid of regular perturbation method.Effects of the magnetic field M,and the Hall parameter m on the local skin friction coefficient and local Nusselt number coefficient were shown graphically for smaller values of the Prandtl number Pr(=0.005,0.01,0.05).Further,velocity and temperature profiles were also drawn from various values of local transpiration parameter.
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Key words:
- MHD natural convection /
- Hall current /
- permeable plate /
- heat flux
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