Mode Identification of Complex Pressure Oscillations in a T-Burner and Preliminary Analysis of Mach Number Effects

Building upon the framework of Natanzon’s solutions, an analytical model is derived from the linearized Euler equations in cylindrical coordinates, yielding explicit Mach number dependent expressions for resonance frequencies and pressure perturbation distributions. A dedicated pulse‑triggered T‑burner experiment with multi‑point high‑frequency pressure transducers is designed and conducted. Through time‑frequency and phase analyses of the recorded signals, the coexisting first‑order axial and tangential modes are tentatively identified during the transient exhaust phase. Both the axial and tangential frequencies exhibit a negative correlation with the mean Mach number. As a preliminary extension, a stability analysis for a simplified solid rocket motor indicates that variations in the Mach number can shift the combustion instability boundary, implying that mean‑flow effects may have a nontrivial influence on stability assessments.