Summary

The present study considers an assessment of numerical methods to predict the fluid flow and the acoustic noise of subsonic jets (M = 0.9 and Re=1.38x106). Additionally, the roles of chevron nozzles on the flow development and as a passive noise control device are also investigated. The adopted hybrid simulation approach initially solves the turbulent field flow, which is then used as input data for estimates of far-field noise. Two turbulence models within the frame of the Reynolds averaging concept were tested for the field flow solution: the cubic k-e model and the Reynolds stress transport model. Moreover, predictions of acoustic noise were carried out through the Lighthill analogy and the Ffowcs-Williams and Hawkings analogy. Comparisons between numerical and experimental results for velocity and Reynolds stresses showed that the aforementioned turbulence models are capable of satisfactorily predict the effect of chevron nozzles on the field flow. On the other hand, the methods based on the two acoustic analogies implemented in the commercial software CFD++/CAA++ were seen to be inadequate for estimates of noise in all flow conditions.

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