Tracking and Evolution of Compressible Turbulent Flow Structures
Abstract
An algorithm is introduced to track the evolution of individual structures in turbulent flows. Flow structures are defined as closed surfaces of any kind in numerical or experimental data sets. To track evolving structures over time and to capture their interactions with each other, correspondences between structures in consecutive time steps are found in a higher-dimensional feature space, which is constructed from differential geometric and spatial structure attributes. After detected correspondences are tested for physical realizability, structure interactions are mapped into a graph data structure which represents the evolution and interactions of all tracked structures over time. The hybrid attribute- and region-based algorithm allows large sampling intervals in the database by capturing complex compound interactions resulting from fast feature dynamics. The tracking graph is queried to retrieve individual and statistical information on the evolution of the structures. Graph data mining techniques are adapted to recognize common patterns in the flow feature evolution. In a first application, the tracking algorithm is utilized to conduct a structure-based numerical analysis of passive scalar mixing in decaying homogeneous isotropic turbulence (DHIT) and shock-turbulence interaction (STI) canonical configurations. Structures of a scalar field are defined as disconnected isosurfaces of the particular underlying scalar field in shock-capturing direct numerical simulations (DNS) of DHIT, with Taylor microscale Reynolds number Re lambda = 40 and turbulence Mach number Mt = 0.2, and STI cases in which the turbulence is processed by a shock wave at Mach numbers M = 1.5 and 3.0. The analysis focuses on the temporal evolution of ensembles of passive scalar structures, initialized as collections of uniformly spaced spheres of varying scales, commensurate with the initial Taylor microscale, lambda, of the underlying turbulence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 23, 2022
- Accession Number
- AD1226638
Entities
People
- Jonas Buchmeier
Organizations
- University of Southern California