论文标题
湍流边界层和多孔介质之间的信息传递
Information transfer between turbulent boundary layer and porous media
论文作者
论文摘要
在可渗透壁上和下方的流量之间的相互作用是多孔培养基研究的核心主题。虽然先前的研究为这两个区域之间的强烈耦合提供了令人信服的证据，但很少有研究能够定量测量这种相互作用的方向性，即因果关系。为了阐明问题，我们使用转移熵作为标记来评估自由湍流与多孔介质之间的因果相互作用，并使用界面分辨的直接数值模拟。我们的结果表明，多孔培养基的孔隙率对表面表面相互作用的强度，时间尺度和空间程度具有深远的影响。对于等于0.5的孔隙率值，自上而下和自下而上的相互作用是不对称的，前者主要受小近壁涡流的影响。随着孔隙率的增加，自上而下和自下而上的相互作用都由剪切流不稳定性主导。
The interaction between the flow above and below a permeable wall is a central topic in the study of porous media. While previous investigations have provided compelling evidence of the strong coupling between the two regions, few studies have quantitatively measured the directionality, i.e., causal-and-effect relations, of this interaction. To shed light on the problem, we use transfer entropy as a marker to evaluate the causal interaction between the free turbulent flow and the porous media using interface-resolved direct numerical simulation. Our results show that the porosity of the porous medium has a profound impact on the intensity, time scale and spatial extent of surface-subsurface interactions. For values of porosity equal to 0.5, top-down and bottom-up interactions strongly are asymmetric, the former being mostly influenced by small near-wall eddies. As the porosity increases, both top-down and bottom-up interactions are dominated by shear-flow instabilities.
