Proper orthogonal decomposition analysis of the flow field in a plane jet
| Autor: | Rajnish N. Sharma, Peter Richards, Young-Min Shim |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Jet (fluid) Sideband Plane (geometry) Mechanical Engineering General Chemical Engineering Aerospace Engineering Mechanics Vortex Physics::Fluid Dynamics Nonlinear system Classical mechanics Nuclear Energy and Engineering Particle image velocimetry Proper orthogonal decomposition Vector field |
| Zdroj: | Experimental Thermal and Fluid Science. 51:37-55 |
| ISSN: | 0894-1777 |
| DOI: | 10.1016/j.expthermflusci.2013.06.014 |
| Popis: | An experimental study was performed for the developing structural characteristics of a plane jet at Re = 3000. The velocity field measurements were made using particle image velocimetry (PIV) in a water jet facility. The proper orthogonal decomposition (POD) method was applied to the two-dimensional PIV data to reveal large-scale vortical structures in the jet flow. The symmetrical counter-rotating vortices that have been discussed in previous jet studies were confirmed in the initial region. It was found that these vortices were generated as a result of the first vortex merging at the subharmonic sideband frequency, ( f o ± f c ) / 2 , where f o was the initial jet shear instability frequency and f c was the jet column frequency. Moving downstream, their characteristic frequency evolved into f o / 2 - 3 f c / 4 through nonlinear interaction. In the interaction region, symmetrical vortices were gradually displaced with each other in the streamwise direction and antisymmetrical vortices were eventually formed. The negative correlation between streamwise velocity fluctuations at two points on opposite sides of the jet centreline was caused by the passage of vortical structures. |
| Databáze: | OpenAIRE |
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