CAA STUDY OF ENTROPY NOISE IN NOZZLE FLOW FOR THE VALIDATION OF A 2D SEMI-ANALYTICAL MODEL

Analytical methods address the need to quickly determine the effect of indirect combustion noise on farfield acoustic emissions and combustion instabilities in order to account for them in new designs. A 2D axisymmetric model for indirect combustion noise through a non-compact nozzle was recently developed by Zheng et al. with this ambition [PhD Thesis, 2016]. An original Computational AeroAcoustics (CAA) approach is applied to serve as a reference case within a framework close to the model's hypotheses. Results from computations with a Euler mean flow field are compared to the model. Very good-agreement is observed, validating the approach. The data is also compared to a 1D model for the non-compact nozzle elaborated by Giauque et al. [J. Eng. Gas. Turb. Power, 134, 2012], demonstrating the importance of 2D effects and the role of radial deformation of the entropy wave.