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• ANNUAL REPORT 2013
Autonomous Underwater Vehicles (AUV)
for operations under ice: subsurface
monitoring of sea ice and icebergs
Unmanned underwater vehicle technology has matured
to a point where it is possible to use these types of
vehicles for deep water, long endurance missions. The
Arctic seafloor remains one of the last unexplored
areas on Earth, but unmanned underwater vehicles are
starting to change this. From the first deployment of
autonomous underwater vehicles in the Arctic in 1972,
these vehicles have in the later years been used in more
complex and longer missions.
Underwater sensor platforms are particularly inter-
esting to ice management operations in the Arctic, due
to the stability of the environmental conditions under-
water. Petter Norgren is studying the use of autono-
mous underwater vehicles to 1) Underwater iceberg
survey as input to iceberg drift forecasting and iceberg
stability for towing operations, 2) Underwater monitor-
ing of sea ice.
Norgren started his PhD studies in March, 2013. In the
early stage of his PhD, he got involved in planning and
preparing for underwater-vehicles tests for OATRC2013.
He participated in the cruise and returned with useful
field experience, data and ideas for his further work.
Based on this experience and a literature review, Petter
wrote a conference paper that will be published in
IAHR’14.
Multi-scale modelling of iceberg drift and
its application to ice management
The presence of icebergs in an offshore field will have
a significant influence on the concept selection for the
development of that field. To estimate the probability
and frequency of icebergs passing a certain area, one
should have a validated large-scale model for iceberg
drift. One of the key elements of a model is to estimate
the deterioration of the iceberg mass which has strong
effects on its dynamics.
Marat Kashafutdinov has developed a numerical model
to couple the drift and thermal erosion of an iceberg.
The iceberg in the model is subjected to forces from
wind, waves and currents. Linear wave theory is used
to describe the velocity potential in the vicinity of the
iceberg surface which allows the calculation of wave
forces and the estimation of heat transfer coefficients.
These coefficients are used to estimate the inward heat
flux which may cause the melting i.e. iceberg mass loss.
PhD candidate Kashafutdinov is making a progress in
writing a journal paper describing the development of
the numerical model and the main findings.
Figure 14. Simulation of iceberg erosion during 10 days due
to waves. The wave height is 1 m and wave period is 10 s.
The temperature of the iceberg is set to -8˚C; the water and
air temperatures are +1˚C and +10˚C, respectively.