Yoshitaka Matsuzaki

In situ estimates of horizontal turbulent diffusivity at the sea surface for oil transport simulation

Despite many previous in situ estimates of horizontal diffusivity below the sea surface, horizontal diffusivity at the sea surface, which is a parameter required in the prediction of oil diffusion, has not been formulated. This study conducted in situ estimations to quantify horizontal diffusivity at the sea surface. To measure the horizontal diffusivity at and below the sea surface, clusters of thin sponge rubbers (simulating spilled oil), together with drifting buoys, were deployed on successive occasions in Sagami Bay, Japan. The experimental results revealed that horizontal diffusivity was larger at the sea surface than below. Based on the results, a procedure for estimating horizontal diffusivity at the sea surface was introduced to predict the diffusion of spilled oil, which was verified using numerical simulations. The simulation results showed good agreement with observations, suggesting the procedure is appropriate for the estimation of horizontal diffusivity at the sea surface.

Development of Smartphone-embedded telemetry drifting buoy for tracking drifting oil patches in the coastal water and field test

For accurately tracking drifting oil patches, a new real time telemetry drifting buoy has been developed. The developed buoy, which utilizes Android smart phone as an electronic device for sensing and telecommunication, can provide its position and additional meteorological data such as wind velocity and direction via cellular phone communication network in real time. The developed buoy is very simple, light weight, cost beneficial as well as high performance so as to contribute to improvement of spilt oil tracking. We conducted field tests using the prototype buoys two times. In the first trial in 2012, we verified its basic function and found that our design concept was rational and found some minor modification could give the system practical usage. In the second trial in 2013, improved prototype buoys were deployed to the field test. In the field test, the buoy worked in nearshore area for many hours without human intervention nor network communication errors and supplied good-quality real-time meteorological data. The obtained data were analyzed and found very useful for tracking drifting oil patches on the sea surface since the buoy provides not only water current information but also wind information. They are also contributory to modeling horizontal turbulent diffusivity of oil patches. This paper shows the design of the buoy and the performance in the field tests. As for the application, this paper also presents a new oil tracking method using the buoy as well as discussion about turbulent diffusivity modeling.

Experimental study on friction loss of W/O emulsion in pipelines and its reduction methods.

In the turbulence of ocean wave, spilled oil takes sea water as small droplets dispersed in it, which is referred to as W/O emulsion. The resultant W/O emulsion has very high viscosity and changes ...

Experimental studies on drift characteristics of heavy oil and drift objects in laboratory tank and coastal area

In this study, drift experiments were carried out using thin drifting mat in the real sea and the validity of real-time data was examined. In the real sea, it is difficult to conduct drift experiments using real oil. Before the experiment, drift experiment had been done in the laboratory tank and a better drifting object was selected for the real sea experiment. By comparing heavy oil and the thin rubber mat, we found drift speed of oil slick and the rubber mat are similar, the thin rubber was used for drift experiments in the real sea.