On the unsteady dynamics of partially shrouded compressible jets
| Autor: | Ashoke De, S. K. Karthick, Soumya Ranjan Nanda, T. V. Krishna, S. Mohammed Ibrahim |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Jet (fluid) Astrophysics::High Energy Astrophysical Phenomena Nozzle Fluid Dynamics (physics.flu-dyn) Computational Mechanics FOS: Physical sciences General Physics and Astronomy Mechanics Physics - Fluid Dynamics law.invention Physics::Fluid Dynamics Flow separation Mechanics of Materials law Schlieren Shielded cable Compressibility Free expansion Noise (radio) |
| Popis: | We experimentally investigate a partially shrouded sonic jet (a sonic free-jet shielded by a solid wall-extension on one side) exiting from a planar nozzle at two different nozzle pressure ratio ($\zeta=4$ and $5$). We experimentally show that the inherent jet unsteadiness from the shock-induced flow separation on the wall and the emitted noise in the far-field is strongly coupled through a series of experiments like high-speed schlieren, wall-static pressure, unsteady pressure spectra, and microphone measurements. The partially shrouded jet's lateral free expansion is also identified to be complicated, three-dimensional, and the produced noise is directional. The emitted acoustic pulses from the flapping-jet, the radiated noise from the shock-induced separation on the wall, and the shock-shear layer interaction on the other side of the wall are responsible for the generated acoustic disturbances. The non-uniform aeroacoustic forcing on the top and bottom portion of the partially wall-bounded jet shear layer leads to a self-sustained jet oscillation and a discrete sound emission. The vital features are identified through the proper orthogonal decomposition of high-speed schlieren images and supplemented by other measurements. Comment: 14 pages, 8 figures, contains 3 videos, article accepted in 'Experiments in Fluids' on September 20, 2021 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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