Visualization of coherent structure in scalar fields of unsteady jet flows with interferometric tomography and proper orthogonal decomposition
| Autor: | B. J. Pelliccia-Kraft, David W. Watt |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Flow visualization Jet (fluid) Computational Mechanics Scalar (physics) General Physics and Astronomy Orthogonal functions Near and far field Computational physics Vortex Vortex ring Physics::Fluid Dynamics Classical mechanics Mechanics of Materials Scalar field |
| Zdroj: | Experiments in Fluids. 30:633-644 |
| ISSN: | 1432-1114 0723-4864 |
| DOI: | 10.1007/s003480000241 |
| Popis: | Proper orthogonal decomposition (POD) is a method of examining spatial coherence in unsteady flow fields from an ensemble of multidimensional measurements. When applied to experimental data, the proper orthogonal decomposition is generally restricted to data sets with low spatial resolution. This is because of the inherent difficulties in generating an ensemble of measurements that contain a large number of data points. In this paper, a system for obtaining a large ensemble of three-dimensional scalar measurements using interferometric tomography is presented. The proper orthogonal decomposition is applied in three spatial dimensions to experimental data of two jet-like flows. The coherent structure present in the near field of a neutrally buoyant, helium–argon jet and the far field of a buoyant helium jet into air is visualized. The POD results of the helium–argon jet clearly reveal the breakdown region of a sequence of vortex rings and a large-scale flapping motion in the jet far field. The POD of the buoyant helium jet shows a number of competing modes with varying degrees of helicity. |
| Databáze: | OpenAIRE |
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