Research on Underwater Acoustic Propagation Characteristics on Underwater High-Speed Cross-Gradient Motion Navigation Platform

The intricate underwater environment, particularly within the ocean, profoundly influences sound propagation characteristics. This study centers on the challenges of acoustic propagation within high-speed cross-gradient moving aquatic vehicles. It delves into the alterations in underwater sound sign als arising from dynamic factors like pressure fluctuations, shif ts in sound speed gradients, and motion-induced cavitation. Ini tially, the xx model analyzes flow fields, explicitly focusing on p ressure dynamics and phase transitions at the vehicle's forefront. Both two-dimensional and three-dimensional models are em ployed to simulate and dissect the swiftly moving vehicle's cavit ation and flow field attributes. Subsequently, drawing from the equation governing sound propagation in bubbly liquids, the r esearch investigates the effects of dynamic pressure, air density changes, and variable sound speed. This process leads to the d eveloping of a sound propagation model tailored to high-speed cross-gradient moving vehicles, offering insights into variations in sound speed, attenuation amplitude, and resonant frequenc y with depth. The study's findings unveil that during vertical n avigation at a speed of one hundred knots, the bubble layer pre dominantly congregates on the sides and rear of the vehicle. W hen moving swiftly with a 3° angle, the asymmetric distribution phenomenon appears in the head flow field. Moreover, as the v ehicle accelerates, sound speed attenuation becomes more pron ounced nearer the sea's surface. Conversely, the reduction in so und amplitude attenuation is less marked. Changes in resonant frequencies exhibit reduced prominence, while nonlinear effec ts intensify as the vehicle's speed escalates.