六角球堆积中非线性振荡流模型的评估
Assessment of models for nonlinear oscillatory flow through a hexagonal sphere pack
AI总结：
本研究评估了六角球堆积中非线性振荡流的多孔介质模型，发现扩展动态渗透率模型在低频和中频表现良好，但高频时Forchheimer系数高估阻力；非稳态Forchheimer方程在非线性流中误差较小，源于惯性项与非线性项的误差抵消。
摘要：
我们回顾了体积平均框架下的非稳态多孔介质流动模型，并讨论了模型之间的理论关系以及模型系数（及其不确定性）的定义。将不同模型与六角球堆积中振荡流的直接数值模拟进行了比较。模型常数根据其在斯托克斯流、势流和稳态非线性流中的定义来确定。因此，模型预测与模拟数据之间的差异可归因于模型参数化的不足。我们发现，Pride等人[Physical Review B 47(9), 1993]的动态渗透率模型扩展一个Forchheimer型非线性项，在线性流以及低频和中频非线性流中表现良好，但基于稳态获得的Forchheimer系数在高频时高估了非线性阻力。该模型在低频时简化为非稳态Forchheimer方程，其加速度系数基于静态粘性曲折度。基于动态曲折度高频极限的加速度系数的非稳态Forchheimer方程，在中频和高频线性流中误差较大，但在所有频率的非线性流中误差较小。这可通过惯性阻力与非线性阻力之间的误差抵消来解释。
英文摘要：
We review models for unsteady porous media flow in the volume-averaging framework and we discuss the theoretical relations between the models and the definition of the model coefficients (and the uncertainty therein). The different models are compared against direct numerical simulations of oscillatory flow through a hexagonal sphere pack. The model constants are determined based on their definition in terms of the Stokes flow, the potential flow and steady nonlinear flow. Thus, the discrepancies between the model predictions and the simulation data can be attributed to shortcomings of the models' parametrisation. We found that an extension of the dynamic permeability model of Pride et al. [Physical Review B 47(9), 1993] with a Forchheimer-type nonlinearity performs very well for linear flow and for nonlinear flow at low and medium frequencies, but the Forchheimer term with a coefficient obtained from the steady-state overpredicts the nonlinear drag at high frequencies. The model reduces to the unsteady Forchheimer equation with an acceleration coefficient based on the static viscous tortuosity for low frequencies. The unsteady Forchheimer equation with an acceleration coefficient based on the high frequency limit of the dynamic tortuosity has large errors for linear flow at medium and high frequencies, but low errors for nonlinear flow at all frequencies. This is explained by an error cancellation between the inertial and the nonlinear drag.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
