Although this question has already been asked a number of times, we have no knowledge of cases in which couplings have been realized in practice.
I suppose that in principle coupling WEST with a CFD tool (Fluent, OpenFOAM, COMSOL, ...) could mean 2 things: either the CFD tool is called from WEST to provide a more detailed modeling of a certain unit process (e.g. clarifier), or the CFD tool calls WEST to perform some additional computations for each grid cell. Both are most likely technically possible.
In the case of WEST calling a CFD tool for detailed modeling of a unit process, a piece of MSL code could be written that calls an external C-callable function. In this function the CFD tool would then be called. Some CFD tools may have an API through which such calls can be performed, others may have a command-line executable version that can be launched as an external OS process.
In the case of a CFD tool calling WEST, one would have to use the CFD's tool mechanism for calling custom functions (in Fluent these are called UDF's I believe). From such a custom function, the WEST API (*not* WEST as a whole) can then either be invoked to perform certain computations, or the WEST command-line executor (texec.exe) can be launched as an external OS process.
For your information, DHI in general has ample experience with CFD modeling, as is attested by the document below. Information about commercial services (e.g. in relation to coupling to WEST or any other MIKE by DHI software) is available upon request.
[url=http://userarea.west.mikebydhi.com/Download/Public/CFD%20Modelling%20by%20DHI%20SOQ.pdf]http://userarea.west.mikebydhi.com/Download/Public/CFD%20Modelling%20by%20DHI%20SOQ.pdf[/url]
