A semi-empirical jet noise model derived using the energy spectrum function.

摘要

A far-field jet noise acoustic model derived using the energy spectrum function is presented in this thesis. The derivation follows the MGB [1] approach which requires a k-epsilon CFD solution of the jet plume and the integration of a semi-empirical acoustic model. The empirical constants arise in two places---the noise intensity terms and the mean flow effects. This thesis attempts to reduce the empiricism of the self noise intensity term by deriving the two point space correlation and characteristic length and time scales using the energy spectrum function. The two empirical constants characterizing the mean flow effects were not addressed. This thesis builds upon the work done by Frendi et al. [2] in estimating jet noise from a X-33 linear aerospike engine and an axisymmetric Mach 2 nozzle. Good agreement between the model predictions and the X-33 engine noise measurements were obtained using the theoretically derived self noise intensity with no adjustment of the constants. The axisymmetric engine results showed good agreement using Frendi's constants and the theoretically derived space correlation and length scale, but the derived time scale had to be adjusted to fit the experimental data.