Detection of Wavy Sea Surface Oil-Derivative Contamination with Forward Specular High-Frequency Scattering
| Autor: | Ewa Skrodzka, Łukasz Bielasiewicz, Maciej Grzegorczyk, Pawel Rochowski, Stanislaw J. Pogorzelski, Bogumił B. J. Linde |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Marangoni effect
Materials science 010504 meteorology & atmospheric sciences Scattering Mechanical Engineering Naval architecture. Shipbuilding. Marine engineering capillary wave damping VM1-989 Spectral density at-sea pollution detection Ocean Engineering 010501 environmental sciences acoustic surface scattering statistical-frequency analyses 01 natural sciences Signal Molecular physics Spectral line Physics::Fluid Dynamics Amplitude crude oil contamination Ultrasonic sensor Specular reflection 0105 earth and related environmental sciences |
| Zdroj: | Polish Maritime Research, Vol 27, Iss 1, Pp 173-179 (2020) |
| ISSN: | 2083-7429 |
| DOI: | 10.2478/pomr-2020-0018 |
| Popis: | A spectrum of low-frequency (20–30 Hz) amplitude fluctuations of the ultrasonic (10 MHz) signal specularly scattered from water surfaces covered with monomolecular and thicker crude oil origin films of well-defined, oceanographically relevant viscoelastic properties was examined in laboratory and at-sea conditions. The relationship between the surface water wave (30 Hz) damping coefficient and the oil layer thickness was established, and compared to the one predicted by the classical Stokes theory. The depression of the spectral energy density of wind-driven waves by surface films was inferred from the ratio of acoustic signal fluctuations spectra with/without films, and compared to that resulting from the Marangoni damping theory applicable to monolayers of particular surface viscoelasticity. The agreement between the theory and experimental data was satisfactory. As shown in at-sea experiments performed with a free-floating, buoy-like acoustic system, and an artificial oil slick spread over the Baltic Sea surface, the film’s rheological surface properties can be recovered from acoustic surface probing, as well as oil spill edge detection. Simultaneous statistical analyses of the scattered signal amplitude distribution parameters turned out to be unequivocally related to the oil substance fraction weight, oil layer thickness, and the form of oil contamination. |
| Databáze: | OpenAIRE |
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