非稳态分数阶Oldroyd-B流体绕楔形体流动研究

研究了非稳态分数阶Oldroyd-B流体在多孔介质中通过楔形拉伸板的驻点流动问题。基于分数阶Oldroyd-B流体的本构模型建立了动量方程,并在其中引入了浮升力和驻点流动特征。此外,考虑了具有热松弛延迟时间的修正的分数阶Fourier定律,并将其应用于能量方程和对流换热边界条件。接着,采用与L1算法相结合的有限差分法求解控制偏微分方程。最后,分析了相关物理参数对流动的影响。结果表明,随着楔角参数的增加,流体受到的浮升力增大,导致速度加快;达西数越大,介质的孔隙度变大,流体的流动越快;此外,温度分布先略有上升后明显下降,这表明Oldroyd-B流体具有热延迟特性。

Unsteady flow of fractional Oldroyd-B fluid towards a stretched wedge

The unsteady stagnation point flow of fractional Oldroyd-B fluid through a stretched wedge in porous media is studied.Momentum equation is established based on the constitutive model of fractional Oldroyd-B fluid,in which the characteristics of buoyancy and stagnation point flow are introduced.The modified fractional Fourier''s law considering thermal relaxation-retardation time is proposed,which applies in both the energy equation and the boundary conditions of convective heat transfer.The finite difference method integrated with L1-algorithm is utilized to address the governing fractional equations.The influence of various parameters on flow analyzed.The results show that the velocity rises with the increase of wedge angle parameter m and Darcy number.The temperature distribution first increases slightly but then declines significantly,which presents the thermal retardation characteristic of Oldroyd-B fluid.