TITLE : OIL SLICK MOVEMENT ON A RIVER

BY: S ZHUBRIN - CHAM MEI

DETAILS :

• The movement of oil on the surface of the River Irtysh subsequent to a spill is simulated using ROSA (details of ROSA are on the next page).

• The flow is simulated in two dimensions with the depth of the river as a scalar variable.

• The computed results are compared with experimental results.

DETAILS OF ROSA

• ROSA has been developed by CHAM-MEI as a PHOENICS add-on for computing the spread of oil on river surfaces after a spill.

• Complex river geometries can be used, allowing the simulation of realistic scenarios.

• The effect of different wind strengths and directions can be investigated.

• The results are saved as the concentration of oil at a given time and position on the river. The progress of the slick downstream can be monitored

A wind of 7 m/s is presumed to be blowing from the bottom-left corner of the pictures.

Oil concentration after 5 min
Oil concentration after 10 min
Oil concentration after 15 min
Oil concentration after 20 min
Oil concentration after 25 min
Oil concentration after 30 min
Oil concentration after 35 min
Oil concentration after 40 min
Oil concentration after 45 min

DISCUSSION

The following page contains a table showing comparisons between field measurements made at the Irtysh River on 15th August 1995 and simulated results.

Notes:-

• 11.15 means 11 h 15 min am.
• the spill was started at 09 h 45 min am.

Two simulations were made, a quick forecast and a longer calculation. Both simulations were carried out BEFORE the results were known, but with knowledge of the wind conditions.

The predicted results are in good agreement with the measurements, although the length of the slick is underpredicted. The time for the slick to arrive at a fixed point downstream was predicted very accurately, ie to the nearest minute for a 90-minute travel time.

Comparison of predictions with observations