Abstract
Velocity measurements of an axisymmetric underexpanded supersonic
jet operated at a nozzle pressure ratio (NPR) of 2:6 are acquired using a high resolution particle image velocimetry system. The coherent and random fluctuations believed to be responsible for the primary noise generating mechanisms, such as screech, shock associated noise, and turbulent mixing noise have been linked to the proper orthogonal decomposition (POD) modes. The coherent flow variable is reconstructed using the most energetic modes. Effects of the turbulence-shock interactions are examined by evaluating the integral length scales of each component. The turbulence undergoes a compression and re-expansion period as it passes through the shocks within the potential core. A comparison with literature highlights differences in the evolution of the length scales, with emphasis on a priori and a posteriori approaches for decomposing the flow.
jet operated at a nozzle pressure ratio (NPR) of 2:6 are acquired using a high resolution particle image velocimetry system. The coherent and random fluctuations believed to be responsible for the primary noise generating mechanisms, such as screech, shock associated noise, and turbulent mixing noise have been linked to the proper orthogonal decomposition (POD) modes. The coherent flow variable is reconstructed using the most energetic modes. Effects of the turbulence-shock interactions are examined by evaluating the integral length scales of each component. The turbulence undergoes a compression and re-expansion period as it passes through the shocks within the potential core. A comparison with literature highlights differences in the evolution of the length scales, with emphasis on a priori and a posteriori approaches for decomposing the flow.
| Original language | English |
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| Title of host publication | Proceedings of the 7th Australian Conference on Laser Diagnostics in Fluid Mechanics and Combustion |
| Editors | Damon Honnery, Daniel Edgington-Mitchell |
| Place of Publication | Clayton Victoria Australia |
| Publisher | Monash University Publishing |
| Pages | 173 - 178 |
| Number of pages | 6 |
| ISBN (Print) | 9780646948928 |
| Publication status | Published - 2015 |
| Event | Australian Conference on Laser Diagnostics in Fluid Mechanics and Combustion 2015 - Melbourne, Australia Duration: 9 Dec 2015 → 9 Dec 2015 Conference number: 7th |
Conference
| Conference | Australian Conference on Laser Diagnostics in Fluid Mechanics and Combustion 2015 |
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| Country/Territory | Australia |
| City | Melbourne |
| Period | 9/12/15 → 9/12/15 |