Real-time jet-plate interaction noise estimation based on near-field sensor readings

Motivated by the emergence of Ultra-High By-Pass Ratio engines and the consequent increasingly stronger interaction between jet and airframe surfaces, in this work we consider the estimation of the far-field noise radiated by a jet in an installed configuration based on sensor readings in the near field of the jet. We carry out an experimental investigation in which we consider a subsonic jet interacting with a parallel flat plate as a simplified configuration. The real-time noise estimation is performed using empirical transfer functions between far-field observers and near-field sensors. The transfer functions as well as the accuracy of the noise estimation are characterised as a function of the streamwise position of the near-field sensors and jet Mach number. This analysis can provide guidelines for the placement of the near-field sensors for the implementation of closed-loop control strategies.