The problem of harmful resonant pressure fluctuations in solid-propellant accelerators during the initial acceleration of the Ariane 5 space system is considered. An assumption was made regarding the connection of these fluctuations with changes in the geometric characteristics of the P230 accelerators due to the formation of cavities in them according to the burnout regimes filled with solid rocket propellant combustion products. The volumes of cavities formed during propellant combustion were calculated. The engine scheme that arose after the first part of the charge burned out шis considered. It is obvious that the shape of the cavity can be approximated by the Helmholtz resonator model. It is also taken into account that the gradual heating of the upper layers of solid propellant and the associated changes in the wave resistance of the propellant play a role in the appearance of pressure pulsations in the combustion chamber (CC) of a rocket engine. This leads to the rise of resonant phenomena in the formed cavities.

         As a result of considering various resonator systems, the Helmholtz resonator model, which is most suitable for the computational explanation of pressure pulsations, was chosen to describe the physical model of resonance phenomena. Calculations using this model yielded the same frequency as in the results of measurements during the flight operation of the Ariane 5 space system. Next, the direction for solving the problem of reducing resonant oscillations in the combustion chamber is proposed.