142
F. Muttin
is higher and remains moderate, less than around 1 m/s, a boom can be moored to
deviate the pollutant to a sheltered place. For higher current velocity, the strategy is
to tow with one ship or more a boom to collect the oil as a sweeping process. The oil
pollution concerned is the floating fraction. The others are the sinking, diluted and
evaporated fractions [7].
A boom is composed of fabric materials, with a float and a subsea skirt, reinforced
by longitudinal leach and a weighting chain at its bottom. Such device is efficient
to contain oil because of the hydrodynamic of the floating oil above the sea water
along its subsea part. The hydrodynamic efficiency is the scientific challenge mostly
addressed [2, 6, 15, 17]. The leakage modes [3] are studied experimentally [2] and
numerically [17]. Installed in the environment or in an harbour a boom is a coastal
structure who can fails by swinging mooring or material breaking as a consequence
of large stress in the fabric or strong tension in the mooring lines. The structural
behaviour of booms is a scientific challenge weakly studied [11, 12].
The scientific question addressed here is to propose a numerical modelling of
boom considered as a structural component. To that end a finite element method is
used. The results of the model permit to construct a scientifically based response
plan using boom instead of resorting to empirical approach. The numerical results
are compared to an in-situ experiment to validate the model. An oil leakage criterion
based on the boom subsea skirt vertical angulation permits to evaluate the operational
performance of a boom plan in its environment during a given time.
Many boom references are proposed by the manufacturers. Nevertheless, we adopt
the general usage of two main classes to distinguish the different products. The booms
dedicated to high sea and relatively general environmental conditions are made of a
pneumatic floating tube having a diameter around 0.5 m. The skirt height composed
of a single fabric layer can be around 0.75 m. They can be named curtain or inflated
boom. A such material is shown on the following Fig. 7.1.
The booms used in calm water or harbour with safe environmental conditions
are smaller and lighter than curtains. They are composed of a sequel of juxtaposed
vertical rigid bodies assembled between two vertical fabric layers. Their total height
is around 0.7 m. They can be named barrier or rigid boom. The following Fig. 7.2
shows such boom reference.
The chapter is organised as follows. First, a 2D numerical model is described based
on a non-linear elastic cable element. Secondly, a 3D membrane model permits to
enrich the 2D solution by giving the geometry of the boom components and the
internal stress in the constitutive materials. The third part is dedicated to the fullscale experiment carried out in the Elorn estuary, Brittany, France, with the material
shown in Fig. 7.2.
F. Muttin
is higher and remains moderate, less than around 1 m/s, a boom can be moored to
deviate the pollutant to a sheltered place. For higher current velocity, the strategy is
to tow with one ship or more a boom to collect the oil as a sweeping process. The oil
pollution concerned is the floating fraction. The others are the sinking, diluted and
evaporated fractions [7].
A boom is composed of fabric materials, with a float and a subsea skirt, reinforced
by longitudinal leach and a weighting chain at its bottom. Such device is efficient
to contain oil because of the hydrodynamic of the floating oil above the sea water
along its subsea part. The hydrodynamic efficiency is the scientific challenge mostly
addressed [2, 6, 15, 17]. The leakage modes [3] are studied experimentally [2] and
numerically [17]. Installed in the environment or in an harbour a boom is a coastal
structure who can fails by swinging mooring or material breaking as a consequence
of large stress in the fabric or strong tension in the mooring lines. The structural
behaviour of booms is a scientific challenge weakly studied [11, 12].
The scientific question addressed here is to propose a numerical modelling of
boom considered as a structural component. To that end a finite element method is
used. The results of the model permit to construct a scientifically based response
plan using boom instead of resorting to empirical approach. The numerical results
are compared to an in-situ experiment to validate the model. An oil leakage criterion
based on the boom subsea skirt vertical angulation permits to evaluate the operational
performance of a boom plan in its environment during a given time.
Many boom references are proposed by the manufacturers. Nevertheless, we adopt
the general usage of two main classes to distinguish the different products. The booms
dedicated to high sea and relatively general environmental conditions are made of a
pneumatic floating tube having a diameter around 0.5 m. The skirt height composed
of a single fabric layer can be around 0.75 m. They can be named curtain or inflated
boom. A such material is shown on the following Fig. 7.1.
The booms used in calm water or harbour with safe environmental conditions
are smaller and lighter than curtains. They are composed of a sequel of juxtaposed
vertical rigid bodies assembled between two vertical fabric layers. Their total height
is around 0.7 m. They can be named barrier or rigid boom. The following Fig. 7.2
shows such boom reference.
The chapter is organised as follows. First, a 2D numerical model is described based
on a non-linear elastic cable element. Secondly, a 3D membrane model permits to
enrich the 2D solution by giving the geometry of the boom components and the
internal stress in the constitutive materials. The third part is dedicated to the fullscale experiment carried out in the Elorn estuary, Brittany, France, with the material
shown in Fig. 7.2.