New Insight Into Internal Waves for Maritime Applications: A Novel Optical Method With Ocean Experimental Results

• Published in: IEEE journal of oceanic engineering 2021-10, Vol.46 (4), p.1240-1247
• Main Authors: Naresh, Praveen, Santhanakrishnan, T., Awasthi, Ram Lochan, Rajesh, R., Mathew, Basil
• Format: Article
• Language: English
• Subjects: Internal waves; laser beam deflection; Laser beams; Lasers; lateral-effect position-sensing photodetector; maritime applications; Measurement by laser beam; Microscopes; Motion perception; naval anti-submarine warfare (ASW) applications; ocean optics; Optical scattering; Optical sensors; Optical surface waves; Oscillations; Position sensing; Refractive index; Sea measurements; Semiconductor lasers; Surface vehicles; Vehicles
• ISSN: 0364-9059; 1558-1691
• DOI: 10.1109/JOE.2021.3064083

Internal waves generated by the movement of surface and subsurface vehicles in the ocean have specific importance in maritime applications. These types of waves are categorized as forced internal waves. In this article, an attempt using a novel optical method is made to study the forced internal waves that are generated by a large surface vehicle in a controlled sea exercise. The optical method uses a diode laser operating at 635 nm and a lateral-effect position-sensitive photodetector. The laser beam undergoes modulation in both its intensity and beam positions with respect to the density variations that are caused in the stratified ocean by the forced internal waves. The experimental scheme, the system aspect of the optical method, and supporting theoretical aspects are detailed with corroborating experimental results. It is observed that the frequency of the forced internal waves also remains within the band of naturally occurring ambient oscillations in the ocean. The obtained results indicate that the forced internal waves detected by the optical method can be used for detecting the movement of maritime vehicles in the ocean.