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T. Torsvik
often runs in parallel with the evolution of supercomputers. Hence CFD is a field in
constant development and is likely to remain so in the years to come.
There is great diversity in the application of CFD, including industrial areas such
as the aerospace and automotive industry, energy production (nuclear power, hydro power, wind power, petroleum industry), chemical and process manufacturing,
physiological applications related to cardiovascular flow and the respiratory system,
and environmental applications concerning atmospheric and ocean motion, water
and wastewater management, and gravity flows such as avalanches and pyroclastic
flows, to name just a few. In this review we focus on the motion of ocean currents
and waves.
The motion of ocean currents is usually studied with the use of a General Circulation Model (GCM). GCMs constitute a subset of CFD models, and are used
both for atmospheric and ocean modelling. These models are at the core of both
weather forecast models and climate models. Large scale wave motions, such as
tidal waves, are usually well reproduced within the GCM framework, whereas other
wave phenomena, such as wind generated surface waves, usually require dedicated
wave models in order to obtain a realistic representation of the physical processes.
Although we will mainly focus on ocean models in what follows, it is important to
have in mind that ocean processes, and particularly motions near the ocean surface,
cannot be regarded in isolation from what is happening in the atmosphere.
Despite the capabilities of CFD, it is important to emphasize that our ability to
simulate fluid motion does not diminish the importance of more traditional methods
involving theoretical and experimental work, and in situ and remote data recording.
Theoretical and experimental results are required to provide benchmark test cases,
results that a CFD simulation must be able to reproduce to demonstrate that physical
properties of the model are handled correctly. Such exercises are a part of model
validation, and are essential in order to identify errors in the model and calibrate
model parameters.
Once a model is deemed to produce results with acceptable accuracy and reliability, simulations can be used to provide information that is impractical or impossible
to get through the other methods, e.g., filling out the gaps in field measurement data
records due to sparse deployment of measurement instruments, analysing flow scenarios that are too complicated for theoretical study, or providing forecasts of likely
future events. Many scientists and engineers will not need to acquire the skills to
develop CFD models, but as the use of CFD methods expands into new fields of science and engineering,more people will likely find that they need to work with data
from simulations or even run CFD simulations themselves. It is therefore important
also for non-specialists to have some idea about what goes on inside a CFD code,
and what the capabilities and limitations are for these models.
The following review is intended for readers with no prior experience with numerical modelling, and consists of two main parts; (1) a general introduction to numerical modelling, followed by (2) an introduction to ocean modelling. Given the
limited space, this review will only scratch at the surface of each subject to provide
the reader with a picture of what goes on “behind the scene” when we run numerical
models. Several books are available on each of these subjects, and a list of suggested
reading will be provided in connection with each section.
T. Torsvik
often runs in parallel with the evolution of supercomputers. Hence CFD is a field in
constant development and is likely to remain so in the years to come.
There is great diversity in the application of CFD, including industrial areas such
as the aerospace and automotive industry, energy production (nuclear power, hydro power, wind power, petroleum industry), chemical and process manufacturing,
physiological applications related to cardiovascular flow and the respiratory system,
and environmental applications concerning atmospheric and ocean motion, water
and wastewater management, and gravity flows such as avalanches and pyroclastic
flows, to name just a few. In this review we focus on the motion of ocean currents
and waves.
The motion of ocean currents is usually studied with the use of a General Circulation Model (GCM). GCMs constitute a subset of CFD models, and are used
both for atmospheric and ocean modelling. These models are at the core of both
weather forecast models and climate models. Large scale wave motions, such as
tidal waves, are usually well reproduced within the GCM framework, whereas other
wave phenomena, such as wind generated surface waves, usually require dedicated
wave models in order to obtain a realistic representation of the physical processes.
Although we will mainly focus on ocean models in what follows, it is important to
have in mind that ocean processes, and particularly motions near the ocean surface,
cannot be regarded in isolation from what is happening in the atmosphere.
Despite the capabilities of CFD, it is important to emphasize that our ability to
simulate fluid motion does not diminish the importance of more traditional methods
involving theoretical and experimental work, and in situ and remote data recording.
Theoretical and experimental results are required to provide benchmark test cases,
results that a CFD simulation must be able to reproduce to demonstrate that physical
properties of the model are handled correctly. Such exercises are a part of model
validation, and are essential in order to identify errors in the model and calibrate
model parameters.
Once a model is deemed to produce results with acceptable accuracy and reliability, simulations can be used to provide information that is impractical or impossible
to get through the other methods, e.g., filling out the gaps in field measurement data
records due to sparse deployment of measurement instruments, analysing flow scenarios that are too complicated for theoretical study, or providing forecasts of likely
future events. Many scientists and engineers will not need to acquire the skills to
develop CFD models, but as the use of CFD methods expands into new fields of science and engineering,more people will likely find that they need to work with data
from simulations or even run CFD simulations themselves. It is therefore important
also for non-specialists to have some idea about what goes on inside a CFD code,
and what the capabilities and limitations are for these models.
The following review is intended for readers with no prior experience with numerical modelling, and consists of two main parts; (1) a general introduction to numerical modelling, followed by (2) an introduction to ocean modelling. Given the
limited space, this review will only scratch at the surface of each subject to provide
the reader with a picture of what goes on “behind the scene” when we run numerical
models. Several books are available on each of these subjects, and a list of suggested
reading will be provided in connection with each section.