47
d
d
d
i
n
i
i
n
i
32
1
3
1
2
=
∑
∑
=
=
(4.4)
The DSD of a dispersed oil phase is widely discussed in the literature.
Experimental studies mostly found either a Rosin-Rammler distribution (e.g.
Johansen et al. 2013) according to
CDF d
k
d
d
i
i
( ) = −
−
1 exp
α
(4.5)
or a log-normal distribution function (e.g. Malone et al. 2018)
CDF
erf
d
d
d i
( ) = + ⋅
−
⋅
1
2
1
2
2
ln
ln
σ
(4.6)
with d i as median diameter, α and σ spreading coefficients and k i = − ln (0.5) =
0.69. Both functions describe a unimodal size distribution, whereas the RosinRammler distribution is slightly biased towards larger drop diameters in direct
comparison of the two.
4.2 Determination of Drop Size Distributions in Laboratory
and Field Settings
Today, the knowledge on drop formation processes in a subsea oil discharge is based
mainly on small-scale experiments in the lab. A single full-scale experiment
(“DeepSpill”) has been performed off the Norwegian coast in 2000, and some measurements were taken during the Deepwater Horizon (DWH) oil spill in 2010 a
large distance from the wellhead.
For a better understanding of the available datasets and the possibilities to assess
the DSD experimentally in the lab during a future spill, the different available
experimental setups are discussed. Several possibilities for in situ measurements
during a spill are presented, and the existing datasets are critically reviewed.
4.2.1 Pilot-Scale Jet Experiments
Several studies have been performed to determine drop size distributions from
downscaled oil jets entering into seawater at surface conditions, especially since the
DWH oil spill. Masutani and Adams (2001) were one of the first to perform in-depth
4 Jet Formation at the Spill Site and Resulting Droplet Size Distributions
d
d
d
i
n
i
i
n
i
32
1
3
1
2
=
∑
∑
=
=
(4.4)
The DSD of a dispersed oil phase is widely discussed in the literature.
Experimental studies mostly found either a Rosin-Rammler distribution (e.g.
Johansen et al. 2013) according to
CDF d
k
d
d
i
i
( ) = −
−
1 exp
α
(4.5)
or a log-normal distribution function (e.g. Malone et al. 2018)
CDF
erf
d
d
d i
( ) = + ⋅
−
⋅
1
2
1
2
2
ln
ln
σ
(4.6)
with d i as median diameter, α and σ spreading coefficients and k i = − ln (0.5) =
0.69. Both functions describe a unimodal size distribution, whereas the RosinRammler distribution is slightly biased towards larger drop diameters in direct
comparison of the two.
4.2 Determination of Drop Size Distributions in Laboratory
and Field Settings
Today, the knowledge on drop formation processes in a subsea oil discharge is based
mainly on small-scale experiments in the lab. A single full-scale experiment
(“DeepSpill”) has been performed off the Norwegian coast in 2000, and some measurements were taken during the Deepwater Horizon (DWH) oil spill in 2010 a
large distance from the wellhead.
For a better understanding of the available datasets and the possibilities to assess
the DSD experimentally in the lab during a future spill, the different available
experimental setups are discussed. Several possibilities for in situ measurements
during a spill are presented, and the existing datasets are critically reviewed.
4.2.1 Pilot-Scale Jet Experiments
Several studies have been performed to determine drop size distributions from
downscaled oil jets entering into seawater at surface conditions, especially since the
DWH oil spill. Masutani and Adams (2001) were one of the first to perform in-depth
4 Jet Formation at the Spill Site and Resulting Droplet Size Distributions