This paper deals with the unsteady double-diffusive mixed convection flow over an exponentially permeable vertical stretching surface in the presence of Darcy-Forchheimer, Dufour, and Soret (cross diffusion) effects. The unsteadiness in the flow, temperature, and the species concentration fields are due to a time-dependent free stream velocity as well as an exponentially stretching surface velocity. The boundary layer equations are transformed into nondimensional form and solved numerically using an efficient, implicit finite difference scheme in combination with the quasilinearization technique for various governing physical parameters. Numerical computations are displayed graphically to illustrate the Soret, Dufour, and permeability effects on the velocity, temperature, and species concentration profiles. Numerical results for the skin friction coefficient, heat transfer, and mass transfer rates are also presented. The present results are compared with previously published work and are found to be in excellent agreement.

中文翻译：

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指数拉伸表面上的非定常混合对流：达西-前孔多孔介质的影响及交叉扩散。

本文在存在达西-福希海默，杜福尔和索雷特（交叉扩散）效应的情况下，处理了指数渗透性垂直拉伸面上非定常的双扩散混合对流。流量，温度和物质浓度场的不稳定是由于随时间变化的自由流速度以及指数拉伸的表面速度引起的。将边界层方程式转换为无量纲形式，并使用有效的隐式有限差分方案结合准线性化技术对各种控制物理参数进行数值求解。数字计算以图形方式显示，以说明Soret，Dufour和渗透率对速度，温度和物种浓度分布的影响。还给出了皮肤摩擦系数，传热和传质速率的数值结果。将目前的结果与以前发表的工作进行比较，发现结果非常一致。