Numerical investigation on the generation, mixing and convection of entropic and compositional waves in a flow duct
View / Open Files
Journal Title
Journal of Sound and Vibration
ISSN
0022-460X
Publisher
Elsevier
Volume
472
Number
115155
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Rodrigues, J., Bussetti, A., & Hochgreb, S. (2019). Numerical investigation on the generation, mixing and convection of entropic and compositional waves in a flow duct. Journal of Sound and Vibration, 472 (115155)https://doi.org/10.1016/j.jsv.2019.115155
Abstract
Recent models and experiments have demonstrated that indirect noise can be generated via acceleration of either entropic or compositional perturbations through a nozzle. These studies found that the acoustic signature depends on the extent of the dispersion effects on the perturbation waves during the convection process. In this work, numerical simulations are undertaken using the URANS formulation to model the mixing of unsteady entropic and compositional waves in an open-ended flow duct in the transitional regime (2500 < Re < 8100). The flow is perturbed by either heat addition or radial injection of an inert gas that is heavier (argon) or lighter (helium) than air. The computed temperature and mass fraction fields are compared to experimental results obtained using both intrusive and non-intrusive techniques. Agreement with the experimental data is good. The signatures of both perturbations are well captured using two-equation turbulence models. However, they lag behind the experimental results at downstream probe locations, suggesting that the centreline velocity is underpredicted. Dispersion effects on the compositional waves are shown to be insignificant for the system studied here. In the heat addition case, heat loss is found to be a key factor in capturing the correct entropic perturbation for long convection lengths.
Sponsorship
EPSRC DTA/Qualcomm/Rolls-Royce
Identifiers
External DOI: https://doi.org/10.1016/j.jsv.2019.115155
This record's URL: https://www.repository.cam.ac.uk/handle/1810/300206
Rights
All rights reserved