Abstract: This study employs large eddy simulation (LES) to investigate the influence of external transverse disturbances on air curtain dynamics. For an air curtain with a mainstream velocity of 3m/s, we systematically examine flow characteristics under three transverse disturbance conditions: 0m/s (undisturbed), 0.5m/s, and 1m/s, elucidating their impact on air curtain stability. Vortical structures are identified using both Q-criterion and \lambda _2-vortex detection methods, revealing shear-layer oscillation patterns in the air curtain. Spectral analysis of pressure fluctuations at monitoring points demonstrates that higher-order modes dominate in the present cavity flow configuration. The power spectral density (PSD) of dominant modes exhibits exponential decay along the streamwise direction, with the decay rate accelerating as disturbance velocity increases. Dynamic mode decomposition (DMD) analysis of mid-plane pressure fields indicates progressive flow destabilization: the number of unstable modes increases significantly with enhanced disturbance intensity, leading to gradual deterioration of air curtain stability.