MassFLOW-3DTM as a simulation tool for turbidity currents: some preliminary results - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 603

(2008) but challenged by Wynn et al . (2007).
We suggest that flows with a basal-inward helic-
ity, which do not experience excessive overspill at
channel bends, are in equilibrium with the associ-
ated channel and most probably responsible for
the lateral expansion of meander bends. However,
further work is needed to confirm our results and
interpretations. Non-erodible substrates in physi-
cal and numerical experiments should be replaced
by erodible ones to account for sediment erosion
and associated changes in channel geometry and
position.

structures match in a very good way that which
can be observed from laboratory experiments in
both size and shape of the resulting lobes.
An accurate tuning of physical parameters, as
bedload coefficient, turbulent mixing length and
entrainment coefficient, needs to be carried on in
order to match the numerical results with the phys-
ical experiments. At the present stage, the software
is still not capable of modelling fluid regions in
which the grain-to-grain interaction (granular flow
model) plays a fundamental role, such as traction
carpets or regions close to the packed bed where
the sediment concentration is very high. Further
simulations with MassFLOW-3D TM will be per-
formed in order to reproduce accurately the behav-
iour of low concentration turbidity currents and to
further implement into the code the mathematical/
numerical approach most able to deal with high
concentration regions and traction carpets.

CONCLUSIONS

The present work shows the importance of the
synergy between deterministic process-based
modelling and laboratory experiments in order to
achieve a better understanding of the intrinsic
structure of turbidity currents.
Much of the physics of this very complex
environment is still unknown and therefore lab-
oratory experiments need to be carried on in
order to have physical evidence of the processes
involved in these currents. At the present stage,
velocity measurements of the flows can be
obtained quite easily, giving an accurate descrip-
tion of the current structure, whereas concentra-
tion measurements for such dense flows in the
laboratory are still problematic. The interaction
between the packed bed and the flow is still a
crucial point to be investigated. Further testing
and analysis of laboratory data needs to be car-
ried out in order to achieve a better and more
detailed understanding of the physics of these
multi-phase currents, with particular attention to
the high density regions and traction carpets
resulting at the flume bottom.
The software MassFLOW-3D TM is capable of
simulating a variety of flow situations involving
sediment transport, erosion and deposition, tak-
ing into account the influence of the topography
of the area. The software can reproduce accurately
the behaviour of the turbidity currents when flow-
ing along a submerged channel and can recreate
the shape and size of lobes resulting from a turbid-
ity current flowing from a channel into an expan-
sion table, as well as the velocity and concentration
distribution in the flow.
As observed from the numerical results, it is pos-
sible to appreciate how the resulting depositional

ACKNOWLEDGEMENTS

The authors would like to thank our partners in
the MassFLOW-3D project, Det norske oljeselskap,
Statoil, Noreco (Norwegian Energy Company),
Wintershall Norge and Lotos E&P Norge for sup-
port. We thank Flow Science Inc. for co-operation
in the project. We would also like to thank Nicole
Clerx, Menno Hofstra and Roel Dirkx for their pre-
cious help in performing some of the laboratory
experiments and numerical analysis. We further
thank Evgeniy Tantserev for his efforts to write the
governing equations of the mathematical model
for the Appendix and Romain Rouzairol for his
precious support.

APPENDIX I

Multi-phase flow modelling of transport,
deposition and erosion of sediments

Suspended flow

The following system of equations describes multi-
phase flow behaviour for sediment gravity flows.
Generalised equations about suspension flow mod-
elling may be found in Ishii (1975) and Ungarish
(1993) and the suspension flow model implemented
in MassFLOW-3D can be further read about in
FLOW-3D (2009) and Basani & Hansen (2009).
This system consists of seven groups of equations