Print Email Facebook Twitter Jet-installation noise and near-field characteristics of jet-surface interaction Title Jet-installation noise and near-field characteristics of jet-surface interaction Author Rego, L. Avallone, F. (TU Delft Wind Energy) Ragni, D. (TU Delft Wind Energy) Casalino, D. (TU Delft Wind Energy) Date 2020 Abstract The link between jet-installation noise and the near-field flow features of the corresponding isolated jet is studied by means of lattice-Boltzmann numerical simulations. The computational set-up consists of a flat plate placed in proximity to a jet, replicating the interaction benchmark study carried out at NASA Glenn. Installation effects cause low-frequency noise increase with respect to the isolated case, mainly occurring in the direction normal to the plate and upstream of the jet's exit plane. It is shown that the Helmholtz number, based on the wavelength of eddies in the mixing layer and their distance to the plate trailing edge, predicts the frequency range where installation noise occurs. Based on the isolated jet near field, scaling laws are also found for the far-field noise produced by different plate geometries. The linear hydrodynamic field of the isolated jet shows an exponential decay of pressure fluctuations in the radial direction; it is shown that the far-field spectrum follows the same trend when moving the plate in this direction. In the axial direction, spectral proper orthogonal decomposition is applied to filter out jet acoustic waves. The resultant hydrodynamic pressure fluctuations display a wavepacket behaviour, which can be fitted with a Gaussian envelope. It is found that installation noise for different plate lengths is proportional to the amplitude of the Gaussian curve at the position of the plate trailing edge. These analyses show that trends of jet-installation noise can be predicted by analysing the near field of the isolated case, reducing the need for extensive parametric investigations. Subject aeroacousticsjet noise To reference this document use: http://resolver.tudelft.nl/uuid:6bef3dfb-0cad-40e9-8693-6e615c7c698b DOI https://doi.org/10.1017/jfm.2020.294 ISSN 0022-1120 Source Journal of Fluid Mechanics, 895 Part of collection Institutional Repository Document type journal article Rights © 2020 L. Rego, F. Avallone, D. Ragni, D. Casalino Files PDF jetinstallation_noise_and ... action.pdf 1.07 MB Close viewer /islandora/object/uuid:6bef3dfb-0cad-40e9-8693-6e615c7c698b/datastream/OBJ/view