Аннотация:https://doi.org/10.1134/S102833582203003X Received 24 December 2021, Revised 24 December 2021, Accepted 28 January 2022 Published 22 March 2023 Issue Date March 2022 Abstract: The results of a numerical study of the features of gas flows in annular nozzles with an internal deflector in the turbulent flow regime, carried out on the basis of the Favre-averaged Navier–Stokes equations and the Boussinesq approximation for describing the processes of turbulent transfer are presented. Air is considered as a working gas. In calculations using the turbulent model, the starting disturbances accompanying the launch of the nozzle decay, and a “stationary” turbulent regime with high values of the turbulent transfer parameters is established in the cavity of the inner deflector of the annular nozzle, which significantly distinguishes it from the laminar flow regime, characterized by the presence of persistent pulsations of gas pressure on the thrust wall of the nozzle. Funding: This work was carried out in accordance with the research plan of the Research Institute of Mechanics, Moscow State University (project no. АААА-А19-119012990113-1).