Evaluation MethodofRemaining OilProperties inaSunkenShipUsingUltrasonic Technique

Theobject ofthis paper istoclarify theultrasonic oilproperties inasunken ship forseveral kinds ofcrude oil estimation methodforoilproperties whichisnecessary for andfuel oil. recovery fromasunken ship. Weexamined numerical relation Weintroduced waveequations withtheuseofNavior- betweenoilproperties andultrasonic propagationStokes equations expressing motion ofviscous material, and characteristics andintroduced numerical formulas which extracted calculation formulas forultrasonic attenuation in calculate ultrasonic attenuation andreflection coefficients ata viscous material andreflection coefficient atawall-viscous tankwall-oil boundary using oilproperties. Ultrasonicoilinterface, andexamined their characteristics toevaluate attenuation isclosely related withviscosity andweevaluatedoilproperties. their calculated attenuation invarious types ofoilfromapoint ofmeasurement atasunkenship. Themostoilassumedina sunkenship showsquite highattenuation andameasurement ofultrasonic attenuation andvelocity isfound tobeimpractical II. Ultrasonic Propagation Constants toasunkenship. Asanapplicable measurement methodtoa sunkenship, we investigated on ultrasonic reflection phenomenon atsteel-oil interface affected byoilviscosity. In A.WaveEquation inViscous Oil case ofshear wave, thereflection coefficient islargely dependent Ultrasonic propagation constants canbeextracted from onoilviscosity, andthereflection measurement showssome waveequations. TheNavior-Stokes equations describe mo- possibility toviscosity estimation. Incase oflongitudinal wave, tion ofviscous material asfollows (3). thereflection coefficient isfoundtobelargely dependent onoil 1V -V Iap p a® ,4a2V a2V density andbulkmodulus, arealmost free fromoilviscosity. at± x a e p - 3p I p J (1 at ox z paOx 3paOx pya az 2 )