Numerical Evaluation of Jet Noise with Flight Effect for Supersonic Civil Aircraft Using ZDES

This paper investigates numerically the influence of nozzle shape (convergent-divergent or fully convergent) and jet operating conditions on the noise generated by a jet representative of a supersonic business jet at take-off. The nozzle diameter is 50 mm and two operating conditions of Mj = 0.964 and 0.924, corresponding to full thrust and reduced thrust profile, are considered. External Mach number (flight effect) is M0 = 0.31. Jets are fully turbulent with a Reynolds number Re_D ∼ 750, 000. Unsteady flow is reproduced with Zonal Detached Eddy Simulations yielding Wall Modelled LES inside the nozzle (so called ZDES mode 3) together with turbulence tripping to recover an initially turbulent flow. Far-field noise is reconstructed using the Ffowcs Williams and Hawkings integral method. Simulated noise levels are compared to low-order predictions of Stone’s models to assess their reliability for supersonic nozzles. Microphone array processing is used to characterise the position and spectral content of the noise sources and their dependance on nozzle shape and flow condition.