Computation of the noise radiated by a hot supersonic jet deflected in a flame trench

This study aims to numerically investigate the noise radiated by a reduced-scale rocket engine jet at lift-off conditions including a flame trench. An over-expanded Mach 3.1 hot jet entering a flame duct where it impinges on a deflector before being guided in a horizontal duct is considered. The computation is performed with a two-way coupled approach on unstructured grids. This methodology relies on a large-eddy simulation of the jet and the acoustic near field, associated with a full Euler simulation of the acoustic far field. The aerodynamic and acoustic results are compared to a previous computation involving the Ffowcs Williams and Hawkings approach and show a better agreement with the measurements conducted at the MARTEL facility. A more careful analysis of the pressure field suggests that the noise is strongly influenced by the flame trench geometry. Nonlinear propagation effects, natively taken into account by the full Euler solver, are finally highlighted and discussed. Based on appropriate metrics, a good agreement with the experiment is obtained.