Scientific Journals
Zeszyty Naukowe
Maritime University of Szczecin
Akademia Morska w Szczecinie
2012, 32(104) z. 2 pp. 105–109
2012, 32(104) z. 2 s. 105–109
Testing of a oil spill mathematical model contained
in PISCES II simulator
Kinga Łazuga
Maritime University of Szczecin, Faculty of Navigation, Institute of Marine Traffic Engineering
70-500 Szczecin, ul. Wały Chrobrego 1–2, e-mail: [email protected]
Key words: SAR, wind, current, oil
Abstract
PISCES II is a simulator designed to conduct research and training related to the rescue operation in the event
of an oil spill on any of the world region. The program includes a built-in mathematical model, enables the oil
spill of crude oil to observe the interaction in user-specified external conditions. This paper presents the
results of the analysis of mathematical model simulation Pisces II, the behavior of the oil slick in selected
hydrometeorological conditions.
PISCES II – oil spill simulator
observing the processes taking place during the
interaction beetween oil, sea water and air. Also
simulator is used to coordinate rescue operations in
the case of oil spill and training.
Simulator PISCES II is designed to prepare and
conduct rescue action in the case of an oil spill. The
program dive into a comprehensive environmental
information, based on mathematical modeling
of oil spill and its interaction with geographical
restrictions, environmental phenomena, and the
spillage fighting.
Simulator PISCES II is used to predict the
behavior of the oil spill spreading on sea surface,
Oil and processes occurring during
the oil spill
Crude oil is a substance heterogeneous in terms
of both, physical and chemical properities. It is
a mixture of many hydrocarbons and sulfur
Fig. 1. The processes following the oil spill [1]
Zeszyty Naukowe 32(104) z. 2
105
Kinga Łazuga
compounds, oxygen and nitrogen. Due to the diversity of chemical composition of different types of
oil, forecasting the behavior of this substance on
contact centers, such as water and air, is difficult.
Behaviour of oil and its products at the time of filling is determined by physical and chemical properties of spilled substance and external conditions that
accompany this spills.
Oil can also undergo a process such as evaporation, emulsification, dissolution, microbial degradation, which may alter the physical properties of
spilled substance (Fig. 1).
tions the winds of 5, 10, 15, 20, 25 and 30 m/s and
wind direction Kw = 000° were taken into account.
Simulations results are presented in next subsections.
The impact of wind speed for the duration of the
simulation
Wind force has mainly affected the speed of
movement of oil slick on the surface. The figure
below shows the dependence of the duration of the
simulation on wind speed.
Duration of simulation [h]
100
Influance of hydrometeorological
conditions on the simulation results
To see the properties of the simulator PISCES II
model, two points (one point on the Atlantic Ocean
and one point in the North Sea) were taken to simulations.
In the case study of the impact of wind on the
processes taking place in oil slick 100 tons of IFO
300 were used (in form of slick on the surface of
the initial 0.1 km2 and a maximum initial thickness
3.3 mm). In each simulation the wind direction was
north, and its speed was 5–30 m/s.
In the current case study of the impact of surface
processes occurring in the stain 50 and 100 tons of
IFO 300 belongs to a group of medium-sized marine fuels were used.
All simulations were carried out for total annihilation of spilled material from the surface of water
or until the simulation duration exceeded 100
hours.
90
Ts [h]
80
70
60
50
40
26.53
30
20
10
0
7.80
393.00 150.00
5
10
15
20
3.23
1.67
25
30
Wind speed [m/s]
Fig. 3. The duration of the simulation depending on wind speed
Effect of wind speed on evaporation
Evaporation spill (volatilization light fractions
of oil) is very intense. Within one to three weeks of
the uprising even shed about 1/3 of the spilled oil
can evaporate. Oxidation takes place most intensively in the first hours after the oil spillage.
With increasing of wind force and air temperature evaporation is increasing too. Evaporation of
the fraction of light causes an increase in density
and viscosity of spilled oil. Evaporation process,
depending on wind speeds present figures 4 and 5.
20
Evaporation [t]
18
16
14
12
10
8
6
4
Fig. 2. Properties of fuel oil IFO 300
Vw=5 m/s
2
0
"0:00"
"19:00"
"38:00"
"57:00"
"76:00"
"95:00"
"114:00"
"133:00"
"152:00"
"171:00"
"190:00"
"209:00"
"228:00"
"247:00"
"266:00"
"285:00"
"304:00"
"323:00"
"342:00"
"361:00"
"380:00"
Wind effect
One of the main factors influencing the movement of the oil slick is the wind force, which mainly affects the speed of some physical processes
occurring in the oil slick. In the following simula-
Fig. 4. Evaporation of oil during the simulation for wind speeds
of 5 m/s
106
Scientific Journals 32(104) z. 2
Testing of a oil spill mathematical model contained in PISCES II simulator
1.2
25
0.4
120
Vw=15 m/s
Vw=25 m/s
100
Fig. 5. Evaporation of oil during the simulation for wind speeds
of 10–30 m/s
Dispersion [t]
80
Effect of wind speed on the dispersion
Under certain conditions, oil can be dispersed
(the formation of a suspension of microparticles of
oil in water) by mechanical activity of the sea.
The size of dispersion is a function of sea state and
oil properties. Dispersion begins shortly after oil
spillage.
In view of the fact that the sea state is closely
dependent on the wind force dispersion acting most
rapidly with high wind speed [1]. Dispersion
process depending on wind speed present figures 6
and 7.
40
20
Vw=10 m/s
Vw=20 m/s
Vw=30 m/s
"42:00"
"39:00"
"36:00"
"33:00"
"0:00"
0
Speed processes in the oil stain, depending on the
wind
Vw=15 m/s
Vw=25 m/s
Fig. 7. Dispersion of oil in the wind speeds of 10–30 m/s
Figure 8 shows the processes taking place after
the oil spill on the water surface at 15°C, air temperature 20°C and wind speed 15 m/s.
120
100
Amount [t]
Current Impact
Another of the main factors influencing the
behavior of the oil slick in water is a surface current, or tidal current. Current parameters affect
mainly the direction and speed of movement of oil
slick.
80
60
40
Influence of surface current on the processes occurring in the spot crude oil
20
0
If on the oil slick has influance only a surface
current (in this case 10 m/s) and wind speed is 0
m/s, the only process resulting from the action of
this current is the movement of oil slick according
to the current direction (Fig. 9). Changing the direction of current is caused by coastline shape.
Zeszyty Naukowe 32(104) z. 2
60
"30:00"
Vw=10 m/s
Vw=20 m/s
Vw=30 m/s
Fig. 6. Dispersion of crude oil at wind speeds of 5 m/s
"27:00"
0
"24:00"
0
"21:00"
0.2
"0:00"
"3:00"
"6:00"
"9:00"
"12:00"
"15:00"
"18:00"
"21:00"
"24:00"
"27:00"
"30:00"
"33:00"
"36:00"
"39:00"
"42:00"
1
0
"0:00"
"19:00"
"38:00"
"57:00"
"76:00"
"95:00"
"114:00"
"133:00"
"152:00"
"171:00"
"190:00"
"209:00"
"228:00"
"247:00"
"266:00"
"285:00"
"304:00"
"323:00"
"342:00"
"361:00"
"380:00"
2
"18:00"
2.4
5
"15:00"
0.6
3
10
"12:00"
0.8
0.7
15
"9:00"
4.9
Vw=5 m/s
20
"6:00"
1
5
4
30
"3:00"
6
1.4
Dispersion [t]
Evaporation [t]
7
7.4
1.3
Evaporation [t]
8
1
5
9
13
17
21
25
Floating amount [t]
Evaporated amount [t]
Dispersed amount [t]
Fig. 8. Processes occurring after oil spillage at a wind speed of
15 m/s
107
Kinga Łazuga
Fig. 9. The movement of oil slicks at the current speed of 10 m/s
mainly determined by the current parameters. Wind
direction has little effect (3%) to the direction
of movement of oil slick, while the wind speed
determines the speed of most physical processes
occurring in the oil slick.
Impact of current and wind on the behavior of the oil
slick
When on the oil slick in the same time acting
current and wind, movement of this oil slick is
Fig. 10. The direction of movement of oil slick under influence on current (Vc = 10 m/s) and wind (Vw = 10 m/s)
108
Scientific Journals 32(104) z. 2
Testing of a oil spill mathematical model contained in PISCES II simulator
Conclusions
The intensity of evaporation of light petroleum
fractions is dependent on air temperature and wind
force. In the case described below the simulation
temperature was 20°C and the water temperature
was 15°C.
Reported results relate only to simulations of the
physical processes occurring after spillage of IFO
300 oil on the sea surface. Simulations show that
the movement of the slick is mainly influence by
the direction and speed of current. On physical
processes such as evaporation, dispersion, or sinking, the greatest impact has the force of the wind.
It is difficult to determine how fast these processes
will occur after the spillage, because they are
affected by other factors such as air and water
temperature and density of the water. Therefore,
this research will continue.
100
90
80
Amount [t]
70
60
50
40
30
References
20
1. The national plan to combat hazards and pollution of the
marine environment. Maritime Search and Rescue, Gdynia
2005.
2. PISCES II User Manual. Transas Ltd., 2008.
3. Specyfication for PISCES II. Transas Ltd., 2007.
10
0
Floating amount [t]
Evaporated amount [t]
Dispersed amount [t]
Fig. 11. Processes occurring in the oil slick when exposed to
current and wind
Zeszyty Naukowe 32(104) z. 2
109