Analysis of acoustic radiation from instability waves within an off-design supersonic jet flow using combined theory and large-eddy simulation

Abstract

The impact of large-scale turbulent structures on the aerodynamic flow-field and far-field radiated noise is investigated through analysis of an over-expanded supersonic jet. The jet operating conditions are Mj = 1.3 and Reynolds number 1.6 × 106. The Kirchhoff surface (KS) method is used to predict radiated noise based on large-eddy simulation (LES) and applied to calibrate amplitudes of an instability wave model. The acoustic pressure time history in the near- and far-field are constructed with the instability wave model. Predictions are validated with experiment and compare favorably. Cross-correlation and cross-spectral analysis shows that the noise from instability waves is highly correlated the upstream near-field and downstream far-field radiation directions. However, the radiated instability noise in the upstream direction is dominated by fine-scale noise. Results show that it is possible to design a control system for large-scale structure noise based on upstream control if the instability noise can be extracted.