Structural Analysis of Oil-Spill Booms - Mathematical Modelling and Numerical Simulation of Oil Pollution Problems - page 153

theodolite based on a laser ray and a mirror as boom reflector has not been retained
after testing in the preliminary experiment of La Rochelle. Ground vibrations where
the theodolite is installed, generated for example by truck traffic on a harbour quay,
does not permit a precise measure.
7.4.3 Results
Let us describe the measurements obtained from the buoy, the pneumatic boat and
the numerical and experimental analysis on the floating curtain.
Buoy
The water height under the buoy and the boom tension at the mooring point D during
November 5, 2009 are represented on the following Fig. 7.6 . The horizontal axis
represents the time between 00h10 and 22h50.
On Fig. 7.6 we observe that during flooding tide the tension is very low (0.1T).
For ebbing tide (i.e., the tide goes down) the tension is higher (0.33T). At high and
low tides (ebb and flood times) the tension is nearly zero. The remaining question is
how to explain the large difference observed on the tension in term of tide directions.
For the same period of time, we present on the following Fig. 7.7 the boom tension
at point D and the sea current velocity at the buoy location.
We notice that a peak on boom tension corresponds to a peak on the current
velocity. The current velocity is a driver on the boom tension. Nevertheless, it remains
a large difference on this tension between the flooding and ebbing tides. The current
velocity is not the solely reason explaining that effect.
Fig. 7.6 Water height and boom tension during time