CUED Publications database

Direct and indirect noise generated by injected entropic and compositional inhomogeneities

Rolland, EO and De Domenico, F and Hochgreb, S (2017) Direct and indirect noise generated by injected entropic and compositional inhomogeneities. In: ASME 2017 Turbomachinery Technical Conference & Exposition, 2017-6-26 to 2017-6-30, Charlotte, USA pp. 1-13..

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Flow disturbances are generated inside a duct via pulsed injection of helium into a flow of air. This leads to the generation of an acoustic pulse (direct noise), as well as the production of entropic and compositional inhomogeneities which are convected with the mean flow. As these inhomogeneities are convected through a choked nozzle, they generate indirect noise. The resulting acoustic pressure fluctuations are measured experimentally using pressure transducers upstream of the nozzle. Insight obtained from theoretical models and a time-delay analysis can be used to isolate and extract the contributions of direct and indirect noise in the experimental signal. These results are directly compared to existing one-dimensional direct and indirect noise models. The experimental measurement of indirect noise is found to be in good agreement with the theoretical models for entropy noise and compositional noise for a compact one-dimensional isentropic nozzles.

Item Type: Conference or Workshop Item (UNSPECIFIED)
Divisions: Div A > Energy
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 20:03
Last Modified: 10 Apr 2021 00:47
DOI: 10.1115/GT2017-64428