Stability Analysis of Acoustic Models in Undulating Terrain

In the sound propagation experiment conducted in the South China Sea, a comparison between measured and simulated data revealed differences in the sensitivity of various acoustic models to terrain characteristics under identical conditions. To systematically analyze this sensitivity, the models Bellhop, RAM, and KRAKEN were compared against the Couple model under different terrain conditions at receiving depths of 100m and 300m. The results showed that KRAKEN significantly reduces multiple reflections from the seabed and sea surface in sharply undulating terrain. Error analysis indicated that for errors in terrain location, height, and angle, the average errors of Bellhop and RAM at a receiving depth of 100m were 0.67dB, 1.5dB, and 1.33dB lower, respectively, than those at 300m. Furthermore, analysis within the frequency range of 0–500Hz demonstrated that RAM exhibits better stability than Bellhop at receiving depths of 0–200m. This study provides theoretical support for sound propagation simulation under complex terrain and model selection in realistic marine environments.