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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.
Under the action of transverse magnetic field, the effect of Hall current on natural convection of MHD on a vertically permeable plate is studied, and the plate has a uniform heat flux.It is assumed that the induced magnetic field is negligible compared with the external magnetic field.Using the free variable formulation (FVF) And stream function formulation (SFF), the boundary layer equation is reduced to the appropriate form. For the entire range of the partial evaporation coefficient ζ, the parabolic equation obtained from FVF is numerically integrated by the simple finite difference method. On the other hand , The dissimilarity equation obtained by SFF is solved by the local non-similarity method, and some regions are solved by the normal perturbation method if the ζ value of the local evaporation coefficient is large enough or small enough. For the low Prandtl number Pr, for example, Pr = 0.005 , 0.01, 0.05, the effect of magnetic field parameter M and Hall parameter m on the local surface friction coefficient and local Nusselt number are graphically represented.Finally, the velocity and temperature distribution of the fluid are given for different ζ values of local evaporation coefficient.