Xu Jiayi, Dutta Soumya, He Wenbin, Moortgat Joachim, Shen Han-Wei
IEEE Trans Vis Comput Graph. 2022 Mar;28(3):1514-1528. doi: 10.1109/TVCG.2020.3017568. Epub 2022 Jan 28.
Viscous and gravitational flow instabilities cause a displacement front to break up into finger-like fluids. The detection and evolutionary analysis of these fingering instabilities are critical in multiple scientific disciplines such as fluid mechanics and hydrogeology. However, previous detection methods of the viscous and gravitational fingers are based on density thresholding, which provides limited geometric information of the fingers. The geometric structures of fingers and their evolution are important yet little studied in the literature. In this article, we explore the geometric detection and evolution of the fingers in detail to elucidate the dynamics of the instability. We propose a ridge voxel detection method to guide the extraction of finger cores from three-dimensional (3D) scalar fields. After skeletonizing finger cores into skeletons, we design a spanning tree based approach to capture how fingers branch spatially from the finger skeletons. Finally, we devise a novel geometric-glyph augmented tracking graph to study how the fingers and their branches grow, merge, and split over time. Feedback from earth scientists demonstrates the usefulness of our approach to performing spatio-temporal geometric analyses of fingers.
粘性和重力流不稳定性会导致驱替前沿分裂成指状流体。这些指进不稳定性的检测和演化分析在流体力学和水文地质学等多个科学学科中至关重要。然而，先前粘性和重力指进的检测方法基于密度阈值化，这提供的指进几何信息有限。指进的几何结构及其演化很重要，但在文献中很少被研究。在本文中，我们详细探讨了指进的几何检测和演化，以阐明不稳定性的动力学。我们提出了一种脊体素检测方法，以指导从三维（3D）标量场中提取指进核心。将指进核心骨架化后，我们设计了一种基于生成树的方法，以捕捉指进如何从指进骨架在空间上分支。最后，我们设计了一种新颖的几何图形增强跟踪图，以研究指进及其分支如何随时间生长、合并和分裂。地球科学家的反馈证明了我们的方法在对手指进行时空几何分析方面的有用性。
