论文标题

部分可观测时空混沌系统的无模型预测

Flow Characterization in Triply-Periodic-Minimal-Surface (TPMS) based Porous Geometries: Part 1 -- Hydrodynamics

论文作者

Rathore, Surendra Singh, Mehta, Balkrishna, Kumar, Pradeep, Asfer, Mohammad

论文摘要

储层计算是预测湍流的有力工具,其简单的架构具有处理大型系统的计算效率。然而,其实现通常需要完整的状态向量测量和系统非线性知识。我们使用非线性投影函数将系统测量扩展到高维空间,然后将其输入到储层中以获得预测。我们展示了这种储层计算网络在时空混沌系统上的应用,该系统模拟了湍流的若干特征。我们表明,使用径向基函数作为非线性投影器,即使只有部分观测并且不知道控制方程,也能稳健地捕捉复杂的系统非线性。最后,我们表明,当测量稀疏、不完整且带有噪声,甚至控制方程变得不准确时,我们的网络仍然可以产生相当准确的预测,从而为实际湍流系统的无模型预测铺平了道路。

The modeling of flow and heat transfer in porous media systems have always been a challenge and, the extended Darcy transport models for flow and equilibrium and non-equilibrium energy models for heat transfer are being used for macro-level analysis, however, the limitations of these models are subjected to porous geometry. The forced convective flow of an incompressible viscous fluid through a channel filled with four different types of porous geometries constructed using the Triply-Periodic-Minimal-Surface (or TPMS) model, are presented in this study. Four TPMS lattice shapes namely; Diamond, I-WP, Primitive, and Gyroid are created with identical porosity, and three different types of porous media are further generated for each porous geometry to investigate the relationship of shape-tortuosity, microporosity, and pore size on permeability and inertial drag factors. A pore-scale direct numerical simulation approach is performed for the first two types of porous media by solving the Navier-Stokes equations. The specific microporosity is quantitatively induced in the solid region where Darcy-Forchheimer-Brinkman model is solved, whereas the Navier-Stokes equations is solved for the fluid region in the third type of porous media. The results reveal that the validity of Darcy flow regime is very narrow up to Re ~ 4 for the Primitive lattice (Type 1) while for Diamond lattice (Type 2), it extends up to Re ~ 20. For Re > 20, Darcy regime is not valid for any lattice types. For lower porosity (Type 1, ε = 0.32) the inertial drag is found to be minimum in I-WP lattice and maximum in Gyroid lattice while, for higher porosity ( Type 2, ε ~ 1), Primitive lattice has minimum and I-WP lattice has maximum value of inertial drag, respectively.

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