Analysis of wave spectrum for submerged bodies moving near the free surface

The ocean environment is complicated and changing. In ocean engineering, the flow physics around the underwater moving vehicles has been an important research topic. To understand the physical phenomena of submerged bodies in underwater movement and their effect on free surface motion during the moving process, this study treated large submerged bodies, such as submarine and whale, as the research subjects, and integrated dynamic grid technology, volume of fluid method, and finite volume method, to complete their dynamic flow field simulation involving the free surface effect. The dynamic flow simulation of submerged body showed that, the free surface disturbance arising from the moving body is closely related to configuration, dimension, moving speed and submerged depth of the body. Therefore, signal processing technology could be employed to further analyze the characteristics of the disturbed free surface, so as to learn the relationship between the wave spectrum and moving submerged body's geometric and kinematic factors. The proposed research method could not only contribute to analyze the influences of the above mentioned factors on the underwater resistance computation of the marine vehicle, but also allow to further establish the surface wave spectrum database of moving submerged bodies with specific geometric configuration, so as to track and to position the submerged body stealthily.

► Compute the free-surface wave spectrum of underwater moving bodies.
► Employ database of wave spectrum to detect and identify underwater moving objects.
► Spectrum is related to sailing speed, depth, geometric configuration and body size.
► Sailing speed is the most important factor to dominate the wave band range.
► High frequency waves become obvious as sailing depth decreases or speed increases.