The unsteady flow field and flow-induced noise of the expansion chamber under the effect of airflow were numerically simulated and analyzed based on hybrid method. The simulation model based on the finite volume method was established

and the large eddy simulation method was used to calculate the unsteady flow in the expansion cavity. The numerical simulation successfully captured the unsteady flows and the development of eddies in the internal cavity

and agreed well with the experiment results. The flow field results were inserted into acoustic mesh by the integral interpolation method

and then the flow-induced noise sources were calculated by the aeroacoustics theory. The flow-induced noise sources were imported to the acoustic simulation model to calculate the sound pressure at the response points. The acoustic simulation results agreed well with the experiment results on the sound pressure level and resonance frequencies. The results showed that the hybrid method combined the large eddy simulation and the aeroacoustics theory

and revealed the mechanism and process of the flow-induced noise generation in the expansion chamber accurately. The deviations of the tail pipe radiated noise between the simulation results and the experimental results

as well as the theoretical calculation results

were within 5%.