The acoustic analogy has been used as a method of jet noise prediction for severaldecades. Goldstein’s generalised acoustic analogy showed that jet noise can beformulated as the product of a spectral tensor which contains the jet turbulencestatistics and the propagator which controls how the acoustic waves propagateto the far field. In this approach the turbulence enters through the spectral tensor (linearly related to the space-time Fourier transform of the Reynolds stress auto-covariance). The Afsar et al (2011) formulation for heated jets in axisymmetric turbulence showed that the generalised analogy can be related to 11 independent components of the spectral tensor. The main objective of this thesis is to carry out a detailed numerical analysis of the turbulence statistics using LES of four jets. We investigate various turbulence approximations in the spectral tensor model and its impact on acoustic predictions. Our aim is to discover whether universality of turbulence scales exists across Mach number and jet temperature ratio. We found that for jet noise predictions, universality was confirmed across acoustic Mach number, when the jet temperature ratio was fixed. Notably, universality was also found across jet temperature ratio at the peak frequency (St = 0.2, θ = 30). We alsofind several approximations can be made in the spectral tensor calculation toreduce computational complexity. This thesis also considers edge noise, utilising parallel programming across a graphic processor unit to increase computational speed of the predictions as well as improved analytical modelling including optimisation to obtain more accurate acoustic predictions across a range of subsonic Mach number. These results are then combined with the jet noise results to investigate installation effects.
Date of Award | 29 Feb 2024 |
---|
Original language | English |
---|
Awarding Institution | - University Of Strathclyde
|
---|
Sponsors | EPSRC (Engineering and Physical Sciences Research Council) |
---|
Supervisor | Edmondo Minisci (Supervisor) & Paolo Capobianchi (Supervisor) |
---|