Computational Study on the Instability of Supersonic Jet Impingement on a Flat Surface

The lift-off phase of a launch vehicle is characterized by the generation of intense acoustic waves due to the interaction between the supersonic exhaust jet and the launch pad deflector. These pressure fluctuations pose a critical challenge, as they can induce structural fatigue on the launcher and surrounding facilities. Understanding the underlying mechanisms governing the acoustic field in this scenario is essential for mitigating the risks associated with excessive noise levels. In this study, a numerical approach is employed to simulate the supersonic exhaust flow of a Vega-type launcher and its interaction with the launch pad, assuming axisymmetric, inviscid flow. The resulting acoustic field is analyzed using both frequency-domain and time-frequency techniques, providing insight into the unsteady pressure fluctuations. The evolution of dominant frequencies is examined over time, allowing for a deeper understanding of the flow dynamics during lift-off. The results highlight key features of the acoustic environment and provide useful information for future studies on noise mitigation strategies in rocket launches.