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Updated: Oct 1, 2025

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow
Published on: February 27, 2016
Including acoustic modes in the vortex-sheet eigenbasis of a jet
Matteo Mancinelli1, Eduardo Martini1, Vincent Jaunet1
1Département Fluides Thermique et Combustion, Institut PPRIME-Centre National de la Recherche Scientifique-Université de Poitiers-École Nationale Supérieure de Mécanique et d'Aérotechnique, 11 Boulevard Marie et Pierre Curie, Chasseneuil-du-Poitou, 86962, Poitiers, France.
Vortex-sheet models for jets are improved by using a confined jet as a surrogate. This approach accurately captures free-stream acoustic modes, crucial for understanding sound emission and flow-acoustic interactions.
Area of Science:
- Fluid dynamics
- Acoustics
- Computational physics
Background:
- Vortex-sheet (V-S) models are standard for jet dynamics, including Kelvin-Helmholtz instability.
- V-S models often omit free-stream acoustic modes, which are vital for sound emission and flow-acoustic interactions.
Purpose of the Study:
- To introduce a distantly confined jet as a surrogate for free jets.
- To demonstrate that this surrogate effectively incorporates free-stream acoustic modes into the V-S eigenspectrum.
Main Methods:
- Utilizing a distantly confined jet as a surrogate for a free jet.
- Comparing the modal characteristics (eigenvalues and eigenvectors) of the confined jet with those of a free jet.
Main Results:
- Free-stream acoustic waves appear as discrete modes in the confined jet surrogate.
- Eigenvalues and eigenvectors show exponential convergence with increasing wall distance.
Conclusions:
- A distantly confined jet serves as an efficient surrogate for free jets.
- This surrogate accurately reproduces jet dynamics and includes essential free-stream acoustic eigenmodes.
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