<p>This paper investigates the acoustic radiation characteristics of underwater vehicles, specifically focusing on different scales. The research focuses on the bare hull configuration of the Defense Advanced Research Project Agency submarine (DARPA SUBOFF) model, representing the fundamental symmetric structure of an underwater vehicle without propellers or appendages. Numerical simulations were performed on the models in three different scales: 1/24, 1/48, and 1/96. The algebraic wall-modeled large Eddy simulation (WMLES) S-Omega turbulence model was utilized to analyze the flow field around these models under a constant velocity. Hydroacoustic analysis was carried out using the Ffowcs-Williams and Hawkings (FW–H) acoustic analogy. The numerical simulations focused on loading noise and overall noise, which included quadrupole noise. The acoustic spectrum analysis showed that the sound pressure level (SPL) of loading noise and overall noise was mainly concentrated in the low-frequency range and quickly attenuated in the high-frequency range. The loading noise from models at different scales exhibited acoustic similarities. However, the overall noise of models at different scales showed significant scale effects. The proposed numerical approach was comprehensively validated against experimental data for both the hydrodynamic and hydroacoustic fields. These findings provide valuable insights for the design and evaluation of underwater vehicle acoustics.</p>